Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble
Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble
- Page 3: LABORATOIRE D’ASTROPHYSIQUE DE GR
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- Page 28 and 29: • LAOG researchers (and publishin
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- Page 38 and 39: emphasis on the chemistry of planet
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LABORATOIRE D’ASTROPHYSIQUE<br />
DE GRENOBLE<br />
UMR 5571<br />
Scientific Report 2002-2010<br />
Activities: 2002-2005<br />
Research Plans: 2006-2010<br />
December 2005<br />
3
Contents<br />
I Foreword 13<br />
1 15<br />
II Executive Summary 17<br />
1.1 Presentation of LAOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19<br />
1.1.1 A young, fast growing laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19<br />
1.1.2 Evolutions: scientific strategy and team synergy . . . . . . . . . . . . . . . . . . . . . . . 20<br />
1.1.3 A brief overview of the scientific teams of LAOG . . . . . . . . . . . . . . . . . . . . . . . 24<br />
1.1.4 Stu<strong>de</strong>ntship at LAOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25<br />
1.1.5 Selected highlights and comparison with objectives of the previous report . . . . . . . . . 25<br />
1.2 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27<br />
1.3 Relations with the outsi<strong>de</strong> world . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28<br />
1.3.1 Relations with and within the Observatory of <strong>Grenoble</strong> (OSUG) . . . . . . . . . . . . . . 28<br />
1.3.2 Relations with IRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28<br />
1.3.3 Relations with the University and with other local laboratories . . . . . . . . . . . . . . . 29<br />
1.3.4 The European dimension of LAOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29<br />
1.3.5 Publicizing LAOG’s research: outreach and patents . . . . . . . . . . . . . . . . . . . . . 30<br />
1.4 Budget: resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31<br />
1.5 From dreams to reality: Human resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34<br />
1.6 The 2007-2010 prospective and beyond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34<br />
1.6.1 Main scientific objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34<br />
1.6.2 Long-term strategic questions for LAOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37<br />
1.7 Conclusions: A vision for the post-2010 future of LAOG . . . . . . . . . . . . . . . . . . . . . . . 38<br />
5
III Team ASTROMOL 41<br />
2 Presentation and Scientific Objectives 43<br />
2.1 Presentation of Astromol: composition, goals and summary of activities . . . . . . . . . . . . . . 43<br />
2.2 Observations at the telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45<br />
2.3 Development of astrophysical mo<strong>de</strong>ls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46<br />
2.4 Molecular physics: theories and co<strong>de</strong>s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46<br />
2.5 Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47<br />
2.6 Teaching and stu<strong>de</strong>nts formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47<br />
2.7 National and international collaborations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47<br />
3 Results 49<br />
3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49<br />
3.2 Star Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50<br />
3.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50<br />
3.2.2 The <strong>de</strong>uteration in the first phases of star formation . . . . . . . . . . . . . . . . . . . . . 50<br />
3.2.3 The hot corinos of solar type protostars . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51<br />
3.2.4 The outflows of protostars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53<br />
3.2.5 The intermediate/high mass protostars . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53<br />
3.2.6 The X-rays from young protostars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54<br />
3.2.7 Dust around protostars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56<br />
3.3 Molecular Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56<br />
3.3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56<br />
3.3.2 Potential energy surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57<br />
3.3.3 Energy transfer processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58<br />
3.4 High Performance Computing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61<br />
3.5 Proto-planetary Disks: where Astromol meets FOST . . . . . . . . . . . . . . . . . . . . . . . . . 62<br />
4 Perspectives 65<br />
4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65<br />
4.2 Scientific goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65<br />
4.2.1 Star Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66<br />
4.2.2 Molecular Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68<br />
4.3 The involvement in the large international projects: Herschel and ALMA . . . . . . . . . . . . . 69<br />
6
4.4 The European Network “The Molecular Universe” . . . . . . . . . . . . . . . . . . . . . . . . . . 70<br />
4.5 Cosmology: a new frontier for Astromol ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71<br />
4.6 The needs of Astromol : accretion and recruitment . . . . . . . . . . . . . . . . . . . . . . . . . . 72<br />
5 Selected Publications 74<br />
IV Team FOST 77<br />
6 Introduction of the team & Science Results 79<br />
6.1 FOST: a short presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79<br />
6.2 Scientific Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79<br />
6.3 Selected topics in Star Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80<br />
6.3.1 Young Accretion Disks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81<br />
6.3.2 The star-disk interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85<br />
6.3.3 Physics of Jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87<br />
6.3.4 Observations of Debris disks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87<br />
6.3.5 Dynamical Mo<strong>de</strong>ls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88<br />
6.3.6 Other topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88<br />
6.4 Selected topics on the IMF and the properties of low-mass populations . . . . . . . . . . . . . . . 90<br />
6.4.1 Nearby Star Forming Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90<br />
6.4.2 Selected Intermediate Age Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92<br />
6.4.3 The Solar Neighbourhood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93<br />
6.5 Selected topics on Extra-Solar Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96<br />
6.5.1 Exoplanets around M Dwarfs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97<br />
6.5.2 Exoplanets around F- and A-stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98<br />
6.5.3 Exoplanets in Nearby associations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99<br />
7 Future Research Directions 101<br />
7.1 Research Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101<br />
7.2 Needs in personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102<br />
8 Appendices 104<br />
8.1 Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104<br />
8.1.1 permanent staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104<br />
8.1.2 Post-docs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104<br />
7
8.1.3 Graduate Stu<strong>de</strong>nts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105<br />
8.2 Awards and Prizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105<br />
V Team GRIL 107<br />
9 Presentation of the team 109<br />
9.1 Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109<br />
9.2 A specific expertise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109<br />
9.3 Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110<br />
9.4 Related activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110<br />
10 Scientific rationale 111<br />
10.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111<br />
10.1.1 Key astrophysical questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111<br />
10.1.2 Related instrumental evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111<br />
10.1.3 Current trend of large equipments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112<br />
10.1.4 Increasing networking process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112<br />
10.2 Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112<br />
10.2.1 Well <strong>de</strong>fined priorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112<br />
10.2.2 Focusing on three complementary axii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113<br />
10.2.3 The principles of our involvement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114<br />
10.2.4 A logical sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114<br />
11 Results 116<br />
11.1 Towards high dynamic with Adaptive Optics (AO) . . . . . . . . . . . . . . . . . . . . . . . . . . 116<br />
11.1.1 The first generation: NAOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116<br />
11.1.2 The high contrast imaging: VLTPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116<br />
11.1.3 Instrumental Research and <strong>de</strong>velopment activities . . . . . . . . . . . . . . . . . . . . . . 118<br />
11.2 Bringing optical interferometry into mainstream astronomy . . . . . . . . . . . . . . . . . . . . . 120<br />
11.2.1 The classical approach: AMBER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120<br />
11.2.2 The innovative integrated optics: IONIC on the IOTA and VLTI interferometers . . . . . 122<br />
11.2.3 Combining up to eight telescopes of the VLTI array: VITRUV . . . . . . . . . . . . . . . 122<br />
11.2.4 Instrumental Research and <strong>de</strong>velopment activities . . . . . . . . . . . . . . . . . . . . . . 123<br />
11.2.5 JMMC and European Interferometry Initiative . . . . . . . . . . . . . . . . . . . . . . . . 125<br />
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11.3 Cameras and <strong>de</strong>tectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126<br />
11.3.1 Towards wi<strong>de</strong>-field cameras: WIRCam . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126<br />
11.3.2 Research and <strong>de</strong>velopment activities in photon counting superconducting <strong>de</strong>tectors . . . 126<br />
12 Perspectives 129<br />
12.1 Adaptive optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129<br />
12.1.1 Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129<br />
12.1.2 R&D activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131<br />
12.1.3 Means and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131<br />
12.2 Optical interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132<br />
12.2.1 Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132<br />
12.2.2 Software <strong>de</strong>velopment for interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 133<br />
12.2.3 R&D activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133<br />
12.2.4 Means and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134<br />
12.3 Cameras and <strong>de</strong>tectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134<br />
12.3.1 Instrument support technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135<br />
12.3.2 R&D activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135<br />
12.3.3 Means and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135<br />
13 Recruitment plan 137<br />
14 Appendix 139<br />
14.1 Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139<br />
14.1.1 Permanent staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139<br />
14.1.2 PhD stu<strong>de</strong>nts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139<br />
14.1.3 Other contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139<br />
14.2 Main publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139<br />
14.3 Industrial <strong>de</strong>velopment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141<br />
14.3.1 Patents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141<br />
14.3.2 Technological transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141<br />
14.4 Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141<br />
14.5 Awards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142<br />
14.6 Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142<br />
9
VI Team SHERPA 145<br />
15 Results 147<br />
15.1 History and group composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147<br />
15.2 Specific approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147<br />
15.3 Accretion-Ejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148<br />
15.3.1 The self-similar mo<strong>de</strong>l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148<br />
15.3.2 Application to different astrophysical contexts . . . . . . . . . . . . . . . . . . . . . . . . . 148<br />
15.4 Transport phenomena in accretion-ejection flows . . . . . . . . . . . . . . . . . . . . . . . . . . . 150<br />
15.4.1 Jet stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150<br />
15.4.2 Transport in accretion disks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150<br />
15.5 Physics of high energy sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151<br />
15.5.1 Seyfert galaxies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151<br />
15.5.2 Blazars and the “two-flow” mo<strong>de</strong>l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152<br />
15.5.3 Microquasars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153<br />
15.6 Relativistic Plasmas and Cosmic Rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154<br />
15.6.1 Relativistic plasmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154<br />
15.6.2 Cosmic Rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154<br />
15.7 Heavy numerical simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156<br />
15.8 Astrocladistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157<br />
15.9 Participation in large collaborations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157<br />
15.10 Doctoral formation and Schools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158<br />
15.11 Scientific Highlights (2002-2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158<br />
16 Perspectives 160<br />
VII APPENDICES 163<br />
17 Appendix 1: General organization of LAOG 165<br />
17.1 Management structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165<br />
17.2 Management tools and quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166<br />
18 Appendix 2: LAOG Technical group & facilities 167<br />
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167<br />
18.2 Teams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167<br />
10
18.3 Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168<br />
19 Appendix 3: Staff Responsabilities 169<br />
19.1 International . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169<br />
19.1.1 Astromol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169<br />
19.1.2 FOST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169<br />
19.1.3 GRIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170<br />
19.1.4 SHERPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170<br />
19.2 Workshops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171<br />
19.2.1 FOST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171<br />
19.3 National . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171<br />
19.3.1 Astromol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171<br />
19.3.2 FOST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172<br />
19.3.3 GRIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173<br />
19.3.4 SHERPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174<br />
20 Appendix 4: The Jean Marie Mariotti Center 176<br />
20.1 Mission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176<br />
20.2 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176<br />
20.3 Statut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177<br />
20.4 Budget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177<br />
20.5 Direction et personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177<br />
20.6 Le centre <strong>de</strong> réalisation logicielle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177<br />
20.7 Production informatique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178<br />
20.8 Organisation <strong>de</strong> services informatiques distribués . . . . . . . . . . . . . . . . . . . . . . . . . . . 178<br />
20.9 Groupes <strong>de</strong> Recherche et Développement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179<br />
20.10 Formation <strong>de</strong>s utilisateurs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180<br />
20.11 Conduite <strong>de</strong> projets européens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180<br />
20.12 L’Euro-Interferometry Initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180<br />
20.13 Darwin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182<br />
20.14 Relations avec l’ESO et le MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182<br />
20.15 Prospective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183<br />
11
Part I<br />
Foreword: Presentation of the Report<br />
The welcome web page of the LAOG as of October 6, 2005<br />
13
Chapter 1<br />
The last Visiting Committee (known as “Evaluation Committee” in France) of LAOG took place on Jan. 22,<br />
2002, i.e., a little less than four years ago. It examined the activity of LAOG covering the previous period<br />
1999-2001, and its prospective for the period 2003-2006. In the present report, written in preparation for next<br />
Evaluation Committe, set to meet in <strong>Grenoble</strong> on Nov. 3-4, 2005, LAOG scientific activities are <strong>de</strong>scribed<br />
for the period 2002-2005, covered by the previous prospective exercise, and the present prospective covers the<br />
period 2007-2010 (and even beyond, as will be seen). The ”Activity” parts of the report have thus taken place<br />
un<strong>de</strong>r two Directors: C. Perrier until Dec. 31, 2002, and T. Montmerle since Jan. 1st, 2003.<br />
The present document (in English) constitutes the scientific part of the report; the administrative part (in<br />
French), with lists of personnel, <strong>de</strong>tailed budgetary data, etc., is given in a separate document. The complete<br />
bibliography covering the period 2001-2005 is also given as a separate document.<br />
Overall, nearly a <strong>de</strong>ca<strong>de</strong> of scientific activity and projects (prospective) is <strong>de</strong>scribed.<br />
More preci<strong>de</strong>ly, this report tries to summarize in 120 pages not only four years of LAOG actvities (i.e.,<br />
about 400 refereed papers, totalling about 5000 printed pages), but also four to ten years of projects ahead of<br />
us. The presentation is straightforward. As will be explained, the activities of LAOG are now conducted by<br />
four scientific teams. Thus each team <strong>de</strong>scribes its activities and projects in a specific “part” of the present<br />
Report. These four contributions are prece<strong>de</strong>d by an “Executive Summary”, which gives a broad view of LAOG,<br />
explains its structure, and summarizes the activities and projects of the teams in a synthetic fashion.<br />
Several appendices give more <strong>de</strong>tails (see part VII):<br />
- Appendix in chapter 17 gives some information about LAOG’s management structure;<br />
- Appendix in chapter 18 <strong>de</strong>scribes the structure and activities of the Technical group;<br />
- Appendix in chapter 19 lists the national and international science management and responsibilites of LAOG<br />
members;<br />
- Appendix in chapter 20 explains in <strong>de</strong>tail the goals and activities of the “Centre Jean-Marie Mariotti” for<br />
interferometry.<br />
Finally, to help the rea<strong>de</strong>r i<strong>de</strong>ntify what are precisely the scientific contributions of LAOG to a given topic<br />
(as opposed to the work being conducted elsewhere on the same topic), we have resorted to a little typographic<br />
trick when giving references in the text:<br />
- LAOG references (i.e., comprizing at least one LAOG author) relevant to the current activity period (2002-<br />
2005) are given in italics (Laog et al. 2004), and can be found in the list of “selected references” at the end of<br />
each part, and/or in the general bibliography;<br />
- LAOG references to ol<strong>de</strong>r work are given also in italics, but in full (Laog et al. 2000, A&A, 360, 123);<br />
- Non-LAOG references are given in roman, also in full (Nonlaog et al., 2000, A&A, 360, 234).<br />
The Executive Summary part of this report has been prepared by Thierry Montmerle (Director) and Jean-<br />
Louis Monin (Deputy-Director). The team parts have been prepared by the team lea<strong>de</strong>rs: Cecilia Ceccarelli,<br />
François Ménard, Guy Pelletier, Christian Perrier and Pierre Kern (for the Technical group).<br />
<strong>Grenoble</strong>, April 18, 2006<br />
15
Part II<br />
Executive Summary<br />
A 18th century view of the formation of the solar system<br />
17
1.1 Presentation of LAOG<br />
1.1.1 A young, fast growing laboratory<br />
When one takes into account the relatively young age of LAOG as it presently is, i.e., housed in the new<br />
buildings which were completed in 1991 un<strong>de</strong>r the Directorship of C. Bertout, the increase in manpower has<br />
been spectacular, from nearly 40 researchers, engineers, administrative staff and stu<strong>de</strong>nts, to nearly 100 now.<br />
Figure 1.1 shows the evolution of LAOG since 1999, broken down in several categories: (i) permanent staff<br />
(researchers: CNRS, professors and assistant professors [enseignants-chercheurs], astronomers, engineers, technicians<br />
and administrative staff [ITA/IATOS]; (ii) non-permanent staff (contracts, including post-docs; PhD<br />
stu<strong>de</strong>nts [doctorants]). As can be seen from this figure, this fast <strong>de</strong>mographic evolution is due to a combination<br />
of several factors: the hiring of young researchers (8), the return and “accretion” of other researchers from other<br />
institutes (3), the hiring of new engineers (2) (compensating for retirements), an increase in the PhD stu<strong>de</strong>nt<br />
population (9), and, most notably, the arrival of collaborators un<strong>de</strong>r contract (administration, post-docs, etc.;<br />
7).<br />
Figure 1.1: Demographic evolution in LAOG since 1999. The large increase starting in 2000 is due primarily to<br />
the appearance of personnel un<strong>de</strong>r contracts (including post-docs), and also to a strong increase of the number<br />
of PhD stu<strong>de</strong>nts, itself following the increase in the number of researchers (new positions and accretion from<br />
other institutes).<br />
Even though a few staff members will retire during the 2006-2010 period, it is likely that, after some stability<br />
in the last two years (arrivals compensating for <strong>de</strong>partures) there will likely be again a net <strong>de</strong>mographic increase<br />
over the same period, provi<strong>de</strong>d LAOG succeeds in hiring the number of new young researchers (∼ 7 − 9 ?) and<br />
technicians and engineers (∼ 3 − 5) it needs to fulfill its scientific ambitions, as argued in the last section. This<br />
increase does not take into account the possibility that researchers and post-docs from other institutes might<br />
join us, as was the case during the previous period. It is thus likely that the 100-mark will be crossed soon, and<br />
that LAOG will have increased by at least another ∼ 10% in 2010.<br />
In itself, such a strong expansion testifies both to the quality and attractiveness of the work being conducted<br />
at LAOG, and to the continued, unfailing support of national and international research agencies and science<br />
committees, as well as of Université Joseph-Fourier (UJF) of <strong>Grenoble</strong>. The research community as a whole has<br />
supported LAOG by selecting its members for awards: the “Société Française d’Astronomie et d’Astrophysique”<br />
Compaq Prize to one of its young researchers (F. Malbet, 2003), two prizes from the Académie <strong>de</strong>s Sciences to<br />
more senior researchers (J. Bouvier, 2002, and A.-M. Lagrange, 2005), the “Cristal du CNRS” (the highest award<br />
19
of CNRS for technicians and engineers) to LAOG’s Technical Director P. Kern (2004; the second such award<br />
after E. Le Coarer in 1999), and the “Palmes Académiques” (a Ministry of Education award for professional<br />
excellence) to LAOG’s Head of Administration F. Bouillet (2004). In addition, LAOG has had until recently<br />
the highest concentration of “Institut Universitaire <strong>de</strong> France” professors (G. Pelletier as senior member, J.-L.<br />
Monin and G. Henri as junior members).<br />
We thereore believe that LAOG is poised for a bright future and exciting science. As the present report aims<br />
at showing, there is no “growth crisis” at LAOG, because of continuous and sometimes radical adaptation to a<br />
constantly changing and challenging environment. We are convinced that this “Spirit of LAOG”, felt across all<br />
personnel categories, has been one of the strongest assets of this laboratory since its creation.<br />
1.1.2 Evolutions: scientific strategy and team synergy<br />
Major evolutions have taken place at LAOG since 2002, with the aim of better fulfilling its major scientific goals<br />
and of making them more prominent and visible to the community and funding agencies, while accommodating<br />
an ever-growing population. In short, LAOG switched from a research structure of nine small thematic teams<br />
(sometimes as small as three individuals), supported by a technical group, and a theoretical team, to a simpler,<br />
more visible structure of four large teams. This evolution took place in two steps.<br />
• Following the recommendation of the previous Evaluation Committee in 2002 to look for a way to regroup<br />
the existing small scientific teams, and strongly encouraged by the new Director, the LAOG researchers,<br />
after many constructive internal discussions, <strong>de</strong>ci<strong>de</strong>d to create two new “topical” teams, named “Astromol”<br />
and “FOST”, while keeping the theoretical group (Sherpas) intact. (See <strong>de</strong>tails below.)<br />
• After some time, it was however realized that instrumental research activities, central to the building of<br />
new instruments for large telescopes in relation to the scientific goals of LAOG, were not a<strong>de</strong>quately taken<br />
into account. Technological <strong>de</strong>velopments are traditionnally strong at LAOG, and were conducted both<br />
by researchers and high-level engineers on a project-by-project basis. It was thus <strong>de</strong>ci<strong>de</strong>d in mid-2004 to<br />
create a new, transverse group, the “GRIL”, where researchers and engineers would exchange i<strong>de</strong>as and<br />
work together globally, both as an official recognition of instrumental <strong>de</strong>velopments as a genuine research<br />
activity, and as a strategic and advisory group to the Director while keeping the scientific goals of LAOG<br />
in mind. In this team, most of the researchers also belong to one of the topical teams –in practice today<br />
the FOST team. Last but not least, the existence of such a team provi<strong>de</strong>s a correct, visible framework for<br />
PhD stu<strong>de</strong>nts working on instrumental topics.<br />
Figure 1.2 and Figure 1.3 display for comparison the previous organigram (2002) and the new organigram<br />
(2005), which will be discussed in more <strong>de</strong>tail below.<br />
As a result, LAOG today is structured in four roughly balanced research teams (totalling 44 permanent<br />
staff), three topical and one instrumental, and in a technical group which is responsible for conducting the<br />
building of instruments after approval by GRIL (and of course after having been selected by external agencies).<br />
Figure 1.4 displays their respective sizes.<br />
To un<strong>de</strong>rstand these evolutions, and before proceeding to <strong>de</strong>scribe the teams in more <strong>de</strong>tail in the next<br />
section, it is appropriate to start with the main scientific axes <strong>de</strong>veloped over the years since the creation of<br />
LAOG a little more than a <strong>de</strong>ca<strong>de</strong> ago. These can be summarized as follows:<br />
• Origins: the physics of low-mass star formation and early evolution, and the path to planet<br />
formation;<br />
• High energies and astrophysical plasmas: the accretion-ejection phenomenon and its implications<br />
for astroparticle physics;<br />
• Instrumental research: high angular resolution and high dynamic range instruments for<br />
large telescopes.<br />
As schematically illustrated by Figure 1.5, these three scientific axes are strongly interrelated: the study<br />
of the conditions for star and planet formation (disks and jets from young stars and protostars; exoplanets), a<br />
20
Figure 1.2: Old LAOG organigram (2002). The scientific activities were divi<strong>de</strong>d in nine teams, while a separate<br />
“Project group” inclu<strong>de</strong>d all the engineers and technicians.<br />
21
Figure 1.3: New LAOG organigram (2005). Due to internal reorganization, the number of LAOG teams has been<br />
reduced to four (in short: Molecular astrophysics, Star and planet formation, High-energies and astrophysical<br />
plasmas, Instrumental research). The last one, named GRIL, is a transverse group comprizing both researchers<br />
and engineers. The former “Project group” has become a “Technical group”, and its tasks have been subdivi<strong>de</strong>d<br />
into two software groups (one working for the common service of LAOG, the other for instrumental projects),<br />
and in three hardware groups (mechanics, general instrumentation, electronics). The last box lists projects<br />
<strong>de</strong>livered during the current activity period (AMBER, WIRCAM), as well as projects un<strong>de</strong>r <strong>de</strong>velopment. See<br />
text for <strong>de</strong>tails.<br />
22
Figure 1.4: The current repartition of the four LAOG scientific teams. Note that the GRIL team inclu<strong>de</strong>s both<br />
researchers (some being also part of the FOST team) and engineers involved in instrumental research activities,<br />
he total being 4+5=9. The corresponding number counts the main contributors to GRIL not already counted<br />
in the other teams.<br />
major fe<strong>de</strong>rating force at LAOG, requires both high angular resolution and high dynamic range, i.e., contrast,<br />
on the one hand (an instrumental and observational issue) and a study of the accretion-ejection phenomenon<br />
(a theoretical MHD topic, with applications in particular to young stars), on the other.<br />
Figure 1.5: The contributions of the four LAOG scientific teams to their fe<strong>de</strong>rating topic: observations and<br />
theory of the accretion-ejection phenomenon, as keys to the physics of star formation and early evolution (left),<br />
and as a starting point towards exoplanet formation (right).<br />
In the new structure in four teams, it should be stressed that while each team provi<strong>de</strong>s original contributions<br />
to the field of star and planet formation, the teams also have their own specific scientific field of research (e.g.,<br />
fundamental astrochemistry for Astromol, brown dwarfs and exoplanets for FOST, relativistic plasmas for<br />
Sherpas, general research in adaptive optics and interferometry for GRIL). This approach is certainly one of<br />
the main specificities of LAOG when compared to other major international laboratories involved in this field.<br />
In other words, LAOG as a whole is more than the mere sum of its teams.<br />
In contrast, comparing with the previous report the careful rea<strong>de</strong>r will notice that one field of study has<br />
disappeared from LAOG: the structure and evolution of post-main sequence stars. The main reason is the<br />
untimely <strong>de</strong>ath of Manuel Forestini in spring 2003 (a young Assistant Professor, he was not even 40), from a<br />
23
heart attack. Manuel went back to this topic after his well-known work on pre-main sequence (PMS) stellar<br />
evolution. This challenge was all the more formidable that, contrary to PMS stars which draw their energy<br />
only from gravitation, the late stages of stellar evolution involve a highly complex network of nuclear reactions.<br />
His main legacy is the Starevol co<strong>de</strong>, which is publicly available on the web and is now wi<strong>de</strong>ly used by the<br />
stellar evolution community worldwi<strong>de</strong>. In addition to his time-consuming high-level responsibilities at UJF,<br />
Manuel was a whole scientific team in himself, although he was on his way to build a real one with a PhD<br />
stu<strong>de</strong>nt (see Siess and Leclair 2005); when he passed away, however, there was no one to continue this activity<br />
at LAOG. (Fortunately, the field is continuing, chiefly un<strong>de</strong>r Manuel’s former PhD stu<strong>de</strong>nt Lionel Siess, now a<br />
Professor in Marcel Arnould’s group in Brussels.) The proceedings of an international scientific colloquium held<br />
at LAOG in 2004 “Stars and Nuclei: a Tribute to Manuel Forestini” is in preparation (EDP Sciences, edited by<br />
T. Montmerle and C. Kahane).<br />
Ancient Astronomy<br />
One must also mention the work of C. Nozières on History of ancient Astronomy (Michel-Nozières 2002). She<br />
is studying in the original Assyrian language, old astronomical texts on the measurement of the variation of<br />
lunar visibility through the year.<br />
1.1.3 A brief overview of the scientific teams of LAOG<br />
We here give a brief “i<strong>de</strong>ntity card” of each team. The following parts of this report (III to VI) will be <strong>de</strong>voted<br />
to a much more <strong>de</strong>tailed, individual account of their recent activities and prospective.<br />
• The first axis (Origins: low-mass star formation and early evolution, and the path to planet formation),<br />
is shared by all four teams. In alphabetical or<strong>de</strong>r:<br />
(i) the “Astromol” (= molecular astrophysics) team mainly studies the physico-chemistry of the<br />
earliest stages of star formation (molecular clouds, prestellar cores, protostars, and also young disks and<br />
molecular outflows; timescale ∼ 10 5 − 10 6 yrs), but also inclu<strong>de</strong>s fundamental astrochemistry (reaction<br />
rates, transition probabilities, etc.).<br />
Permanent staff: 10. PhDs completed: 2; un<strong>de</strong>rway: 2. Team lea<strong>de</strong>r: C. Ceccarelli (Astronomer).<br />
(ii) the “FOST” (= star and planet formation, brown dwarfs) team focuses on later stages of<br />
star formation, mainly the physics of star-disk interactions, evolved disks and the conditions for planet<br />
formation (structural features like gaps and rings, dust grain evolution in disks, etc.; timescale ∼ 10 6 −10 7<br />
yrs), and also on the formation mechanisms of binaries and the “Initial Mas Function” (IMF). A specific<br />
activity within the team is the study of brown dwarfs, both as astronomical objects by themselves, and as<br />
intermediate bodies between low-mass stars and exoplanets. The search and characterization of exoplanets<br />
are themselves an increasing part of the FOST activities. The team contributes a lot to observations ma<strong>de</strong><br />
with LAOG-built instruments and to their interpretation.<br />
Permanent staff: 13 + 7 shared with GRIL. PhDs completed: 5 + 1 with GRIL; un<strong>de</strong>rway:<br />
9 + 3 with GRIL + 1 with Sherpas. Team lea<strong>de</strong>r: F. Ménard (CNRS).<br />
(iii) the “GRIL” (= instrumental research group at LAOG) team concentrates on strategic issues<br />
in research & <strong>de</strong>velopment (R&D) for future instruments and <strong>de</strong>tectors. While the situation may evolve, so<br />
far GRIL’s responsibility has been to contribute to the <strong>de</strong>velopment of optical and near-IR instruments for<br />
large ground-based telescopes (ESO, CFH) with the highest spatial resolution (for instance with the goal<br />
to resolve the inner parts of protoplanetary disks, i.e., within 1 AU at 450 pc, say), by way of adaptive<br />
optics and interferometry, and/or the highest dynamic range (adaptive optics to image exoplanets as<br />
closely as possible from their host star).<br />
Permanent staff: 9 (including 8 engineers) + 7 shared with FOST. 1 PhDs completed: 3 +<br />
1 with FOST; un<strong>de</strong>rway: 8 + 3 with FOST. Team lea<strong>de</strong>r: C. Perrier (Astronomer).<br />
(iv) the “Sherpas” (= “sources of high energies and relativistic physics in accretion-ejection<br />
structures”, in full) team is essentially involved in MHD theory calculations, with particular emphasis on<br />
the accretion-ejection phenomenon in astrophysics. Here it mainly applies mo<strong>de</strong>ls to star-disk interactions<br />
and disk-driven jets, where magnetic fields, instead of gravitation, play a dominant role.<br />
1 two engineers qualified to supervised PhDs (’HDR’ in french)<br />
24
Permanent staff: 7. PhDs completed: 2; un<strong>de</strong>rway: 2 + 1 with FOST. Team lea<strong>de</strong>r: G.<br />
Pelletier (UJF Professor).<br />
• The second axis (High energies and astrophysical plasmas: the accretion-ejection phenomenon and its<br />
implications for astroparticle physics) is specific to Sherpas team. The team studies the accretion-ejection<br />
phenomenon, here in the context of compact X-ray binaries and AGNs (“two-fluid jets”), where gravitation<br />
(in addition to magnetic fields) plays a dominant role, and also fundamental research on accretion disk<br />
transport and jet stability, as well as cosmic-ray acceleration to ultra-high energies (UHE) by relativistic<br />
shock waves. The Sherpas team is actively involved in the HESS European collaboration, which operates<br />
an array of ˘ Cerenkov telescopes in Namibia with the capability to <strong>de</strong>tect very high-energy γ-rays (≥ 10 12<br />
eV).<br />
• The third axis (Instrumental research in the field of high angular resolution and high dynamic range<br />
for large telescopes), is specific to GRIL. Because of the current wavelength range, there are significant<br />
interactions with the FOST (young stars) and Sherpas (AGNs) teams, but nothing in principle prevents<br />
GRIL to get LAOG involved in mm and/or high-energy instrumentation at the initiative of Astromol or<br />
Sherpas (there are currently no such projects however.) Note that once an instrument reaches the actual<br />
building stage, it leaves GRIL and becomes a “project” of the technical group, hea<strong>de</strong>d by P. Kern. GRIL is<br />
also in charge of helping <strong>de</strong>ci<strong>de</strong> strategic orientations of LAOG for the long-term future, like contributing<br />
to ELTs (extremely large telescopes), interferometric <strong>de</strong>velopments in Antarctica at Dome C, or future<br />
space missions (e.g., Darwin, ESA, > 2015). (These questions will be expan<strong>de</strong>d below.)<br />
1.1.4 Stu<strong>de</strong>ntship at LAOG<br />
Stu<strong>de</strong>nts have always been a large component of LAOG personnel. On average, there are about 20 PhD being<br />
prepared in our lab (6 new stu<strong>de</strong>nts hired every year). The majority of these stu<strong>de</strong>nts get a research grant from<br />
the French Ministry of research, while other are paid by specific grants based on instrumental projects. Since<br />
the year 2001 (TBC), the LAOG also welcomes an increasing number of young researchers on post-doctoral<br />
positions. These positions are awar<strong>de</strong>d by the ministry of research, or the CNRS on the basis of a scientific<br />
project. They are also provi<strong>de</strong>d by the European networks we are more and more involved into. LAOG has<br />
<strong>de</strong>fined a number of procedures to associate its PhD stu<strong>de</strong>nts to the lab every day life:<br />
• two stu<strong>de</strong>nts are elected members of the LAOG advisory board<br />
• every year, we organize a “thesis workshop” during a full day where the PhD stu<strong>de</strong>nts can present their<br />
work before the rest of the lab.<br />
Table 1.1: Number of PhD stu<strong>de</strong>nts from 2003 to 2005 in LAOG<br />
Year 2003 2004 2005<br />
22 16 18<br />
1.1.5 Selected highlights and comparison with objectives of the previous report<br />
Given the large differences between the old and the new structures of LAOG, it is difficult to compare the<br />
prospective of the old teams, as presented in the previous prospective report, and the resulting “activity”<br />
part of the present report, without going into unnecessary <strong>de</strong>tails. The most important changes were due to<br />
movements of researchers leaving or joining LAOG, namely an increase in mm astronomy activities, and the<br />
arrival of a new expertise: X-rays, taken mainly as tracers of magnetic fields in young stars. Most of the other<br />
results have been obtained acording to plans, sometimes even faster (like the first image of an exoplanetary<br />
mass object.)<br />
Consequently, we prefer to summarize the main results obtained by the teams over the 2002-2005 period, as<br />
follows.<br />
25
Figure 1.6: PhD stu<strong>de</strong>nt repartition in 2005. A: ASTROMOL; F: FOST; G: GRIL; S: SHERPAS<br />
• Astromol<br />
• FOST<br />
• GRIL<br />
– Discovery of doubly and triply <strong>de</strong>uterated molecules in low mass star forming regions, from the prestellar<br />
core to the proto-planetary phases. These studies have greatly contributed to the <strong>de</strong>velopement<br />
of a new class of mo<strong>de</strong>ls for the molecular <strong>de</strong>uteration.<br />
– Discovery and imaging of the hot corinos, warm and <strong>de</strong>nse regions at the center of solar type protostars.<br />
These regions, whose sizes are comparable to those of the Solar System, are highly enriched<br />
of complex organic molecules.<br />
– High-accuracy multidimensional calculations of molecule-molecule and electron-molecule interactions,<br />
based upon advanced treatments of electronic correlation.<br />
– State-of-the-art calculations of molecule-molecule and electron-molecule inelastic collisional rates.<br />
These results, whose accuracy rivals available experiments, are of great importance for mo<strong>de</strong>lling of<br />
the interstellar gas from cold regions to harsh environments.<br />
– Direct images of planetary mass companions around 2 objects in young nearby associations: 2MASSW J1207334-<br />
393254 (5 MJup at 55 AU) and AB Pic (13-14 MJup at 250AU) (Chauvin et al. 2004, 2005). These<br />
results were obtained with the NACO adaptive optics instrument, built in part at LAOG.<br />
– Dynamical masses: First astrometric mass <strong>de</strong>termination for a planet, around Gliese 876b: 1.89<br />
±0.34MJup (Benedict et al. 2002). Similarly, astrometric meaurements of stellar masses in binary systems.<br />
Accuracies on the mass of a few percents are reached on nearby L dwarf 2MASSW J0746425+2000321<br />
(Bouy et al. 2004) and ∼ 10% for young stars V773 Tau, DF Tau, and TWA 5 (Duchêne et al. 2003).<br />
– The Universality of the “present day” Mass Function observed down to at least 30 MJup (the sensitivity<br />
limit of the surveys carried) in several young open clusters (e.g., Moraux et al. 2005).<br />
– The very inner structure of young Herbig Be star MWC 297 revealed by NIR interferometry. For<br />
the first time, the respective contributions from the disk and the wind are separated spatially and<br />
spectrally within the inner 1AU of the central source. These results were obtained at the VLTI with<br />
the interferometric recombiner AMBER, built in part at LAOG (Malbet et al. 2005).<br />
– The NAOS (Nasmyth Adaptive Optics System) instrument for the VLT and the AMBER instrument<br />
for the VLTI, partially or fully integrated at LAOG, are now offered to the ESO astronomical<br />
community after successful commissioning and science verification phases (resp. early 2002 and early<br />
2004).<br />
– The VLT-PF (“Planet Fin<strong>de</strong>r”) proposal for a second generation VLT instrument led by LAOG was<br />
selected by the ESO STC in April 2005 after a successfull 2-year phase A study, awaiting formal<br />
<strong>de</strong>cision by the next ESO Council.<br />
– Magnetic or electrostatic <strong>de</strong>formable micro-mirrors have reached full functionality. Magnetic ones<br />
are now ma<strong>de</strong> available through industrial production and an LETI-LAOG electrostatic prototype is<br />
currently un<strong>de</strong>r test.<br />
26
– First fringes in the H band with the IOTA 3 telescopes interferometer by means of an integrated<br />
optics beam combiner (Monnier et al. 2004, Kraus et al. 2005) and first formal <strong>de</strong>monstration of<br />
single mo<strong>de</strong> guiding at 10 microns in the IODA project (Labadie et al. 2005).<br />
– Creation and <strong>de</strong>velopment of the Centre Jean-Marie Mariotti (JMMC) with partners (Nice, and<br />
ASHRA). Consecutive creation of the European interferometry Initiative (EII) coupling interferometry<br />
networks of the OPTICON EC I3, and high-level involvement (PI, PSci) in three of its four<br />
JRAs. The goal of JMMC is to <strong>de</strong>velop user-friendly software, and more generally preparation and<br />
advice, for the use and promotion of the VLTI. (See Appendix in chapter 20<br />
• Sherpa<br />
– Transport of cosmic rays in chaotic magnetic fields. The knowledge of the diffusion coefficients of<br />
cosmic rays is crucial for astrophysical applications and especially for astroparticle physics, both<br />
for mastering the cosmic ray propagation and the efficiency of Fermi acceleration. They have been<br />
computed with a Monte Carlo simulation as a function of the cosmic ray rigidity and the spectrum<br />
of the magnetic field (characterized by its in<strong>de</strong>x and its <strong>de</strong>gree of irregularities). It is found that<br />
the transverse diffusion coefficient follows a law which is nor Bohm nor quasi-linear, but a law that<br />
stems from the analysis of the spatial chaos of field lines. This result is important to estimate the<br />
confinement time of cosmic-rays in galaxies and in extragalactic jets (Casse et al. 2002).<br />
– Stationary accretion disks launching super-fast-magnetosonic waves. This is the last paper in the<br />
series on Magnetized Accretion-Ejection Structures (MAES), which represents the only available<br />
self-consistent mo<strong>de</strong>l of a self-confined jet driven by an accretion disk (with the disk fully resolved),<br />
able to cross all three MHD critical points. Biases induced by the self-similarity contraints are<br />
discussed (Ferreira & Casse 2004).<br />
– On the relevance of subcritical turbulence to accretion disk transport. This paper solves a riddle<br />
dating back to the seventies, and which has given rise to an important controversy in the last ten<br />
years. Namely, it is shown that a linearly stable, keplerian hydrodynamic flow is in<strong>de</strong>ed turbulent<br />
through non linear mechanisms, but that this turbulence has a low efficiency in terms of angular<br />
momentum transport, with a Shakura-Sunyaev parameter α < 10 −5 . The discrepancy between<br />
numerical simulations and laboratory experiments is explained away (Lesur & Longaretti 2005).<br />
– The bulk Lorentz factor crisis of TeV Blazars: evi<strong>de</strong>nce for an inhomogeneous pile-up energy distribution.<br />
It is shown that the theoretical Lorentz factors of Blazar jets are contradicted by the<br />
source statistics which implies Lorentz factors of or<strong>de</strong>r 3, whereas homogeneous mo<strong>de</strong>ls require 50 or<br />
more. The only way out of this conundrum is to take the jet stratification into account, so that high<br />
energy photons are not produced in the same region as low energy ones. Observations then require<br />
mono-energetic distribution functions whereas most mo<strong>de</strong>ls make use of power-law distributions. In<br />
contradistinction with the dominant view, this work shows that (1) jets do not need to be highly<br />
relativistic, and (2) turbulence rather than shocks is at the origin of the production of high energy<br />
particles (Henri & Saugé 2005).<br />
1.2 Bibliography<br />
A major innovation is the creation of an automated bibliography.<br />
Visit http://www-laog.obs.ujf-grenoble.fr/Laog/publications.php. The principle is that, once a list of<br />
names (LAOG personnel, evolving if necessary) is provi<strong>de</strong>d, an automated request is sent to ADS every week.<br />
Thus, new publications (including ArXiv preprints) are regularly ad<strong>de</strong>d to the bibliographical database. It is<br />
recognized that ADS does not cover all publications (for instance it does not access chemistry journals or some<br />
conferences), so that manual corrections and updates are still necessary, which is done un<strong>de</strong>r the responsibility of<br />
the LAOG authors. While this innovation (partly outsourced to a private software company) was implemented<br />
for the present Evaluation exercise, it is a long-term investment and an extremely useful tool that can be<br />
improved in the future (new names, new databases consulted, etc.).<br />
The major quantitative results emerging from the 2001-2005 report bibliography, available in a separate<br />
printed document are as follows: 2<br />
2 The bibliography to be used for the present report (covering the period 2001-2005) is however not exactly i<strong>de</strong>ntical to the web<br />
bibliography. In particular, care has been taken to weed out refereed papers of LAOG members before their arrival or after their<br />
27
• LAOG researchers (and publishing engineers) have published about 400 refereed papers, and about as<br />
many contributions to conferences. This means an average of 80 refereed papers and 80 conference papers per<br />
year, or about 2 + 2 papers per year per researcher/publishing engineer. This result is all the more remarkable<br />
since many researchers have teaching duties (up to 50% of their time), as is the case for several engineers, and/or<br />
important responsibilities in national and international science or advisory committees. (These responsibilities<br />
are listed in Appendix in chapter19.)<br />
• There is a significant, and increasing, number of invited papers in international conferences, on the or<strong>de</strong>r<br />
of 10 per year on average. A notable exception will be in 2005: at the Protostars and Planets V conference<br />
(held every 5-7 yrs since its creation), which is expected to gather 700 participants in Hawaii in late October,<br />
a pre-selection of papers has resulted in 9 invited talks for LAOG, the highest number of the whole community<br />
in the field of Star and Planet formation (the next laboratory is NASA Ames, Calif., with 8 papers). More<br />
generally, LAOG consi<strong>de</strong>rs that part of its scientific policy should be to communicate and exchange results with<br />
the international community in conferences, and <strong>de</strong>votes a significant part of its budget to support this activity.<br />
• The bibliography also lists several patents, relevant to micro- and nanotechnologies, testifying of the will<br />
of LAOG to transfer knowledge to the industry while protecting the intellectual property of its engineers.<br />
1.3 Relations with the outsi<strong>de</strong> world<br />
1.3.1 Relations with and within the Observatory of <strong>Grenoble</strong> (OSUG)<br />
Following a ministerial reform in 1999, the original <strong>Grenoble</strong> Observatory was expan<strong>de</strong>d, including the “<strong>Laboratoire</strong><br />
d’Astrophysique <strong>de</strong> <strong>Grenoble</strong>” (LAOG) and three Earth sciences laboratories (glaciology, hydrology, and<br />
geophysics), as well as a newly created planetology laboratory (the “<strong>Laboratoire</strong> <strong>de</strong> Planétologie <strong>de</strong> <strong>Grenoble</strong>”,<br />
LPG). The new structure, gathering nearly 500 people, became the “Observatoire <strong>de</strong>s Sciences <strong>de</strong> l’Univers <strong>de</strong><br />
<strong>Grenoble</strong>” (OSUG). This reform created a new administrative layer to which the new LAOG had to adapt, but<br />
also brought new resources and new contacts with other fields. Within OSUG, while each laboratory has its own<br />
goals and priorities, new scientific collaborations between LAOG and other OSUG laboratories are emerging,<br />
in glaciology for projects in Antarctica (see GRIL part), and with LPG (dust grain evolution in the young solar<br />
system and young stellar disks, meteorite irradiation, exoplanetary atmospheres, etc.). It is planned to <strong>de</strong>velop<br />
these collaborations in the coming years. It is also worth mentioning that discussions take place from time to<br />
time with the geophysicists on topics such as turbulence and dynamo. The state of the art, or the physical<br />
parameter space (e.g., Reynolds numbers for turbulence), was just too different in the relevant areas for these<br />
collaborations to take place immediately, but the situation is improving.<br />
1.3.2 Relations with IRAM<br />
The roots of LAOG can be found in the GAG (Groupe d’Astrophysique <strong>de</strong> <strong>Grenoble</strong>), a group created by<br />
Alain Omont as a scientific support for the newly created Institut <strong>de</strong> Radioastronomie Millimétrique, IRAM<br />
(1979). Thus most of the founding fathers of LAOG had strong ties with IRAM (the others were the embryo<br />
of the Sherpas group around G. Pelletier), and were in particular heavily involved in mm astronomy. The<br />
new emphasis on high-angular resolution in astronomy in 1991, with a fast hiring of young researchers and<br />
engineers <strong>de</strong>veloping science and optical-IR instruments around this topic, resulted in a <strong>de</strong>cline of the mm<br />
involvement of the newly created LAOG. IRAM, which is by construction a service institute, pursued on its<br />
si<strong>de</strong> the instrumental <strong>de</strong>velopments for the Pico Veleta 30m single-dish radiotelescope and the Plateau <strong>de</strong> Bure<br />
Interferometer thereafter. LAOG researchers involved in mm astronomy either joined IRAM to participate in<br />
its <strong>de</strong>velopment, or continued to use IRAM facilities by way of observing proposals (sometimes including IRAM<br />
co-Is), but the scientific collaborations between the two institutes remained limited, in spite of a few attempts<br />
on both si<strong>de</strong>s (PhD theses, schools...). It is however fair to add that there were on many occasions informal<br />
exchanges between the instrumental teams of LAOG and IRAM. Again, IRAM is a service institute, subject<br />
to the constraints of its funding agencies in Germany and Spain in addition to CNRS in France, and it is not<br />
<strong>de</strong>parture (case of new researchers, post-docs, etc.), references to CDS (Strasbourg) databases (case of tables published only in<br />
electronic form), etc. The difference between the two is about 10% of the total number of publications.<br />
28
clearly in its goals to have scientific activities of its own (although it does have PhD stu<strong>de</strong>nts and post-docs).<br />
This is a constant obstacle to a full-fledged collaboration.<br />
LAOG strongly hopes that this situation will evolve, by promoting together as much as possible activities<br />
around the topic of star formation: common science meetings, formal co-supervision of PhD stu<strong>de</strong>nts, etc. A<br />
common project around a data analysis center for interferometry, CEXIA, is also un<strong>de</strong>r way (see next section).<br />
1.3.3 Relations with the University and with other local laboratories<br />
LAOG is, in the French system, and like most research laboratories, a so-called “Mixed Research Unit” (UMR),<br />
which means that its operations are fun<strong>de</strong>d both by CNRS and the Ministry of Education, via the UJF. In<br />
practice, the University contributes to the operating budget and provi<strong>de</strong>s the buildings, as well as Professors<br />
and stu<strong>de</strong>nt support, while CNRS provi<strong>de</strong>s the scientific equipment and permanent researcher positions. (More<br />
funding and soft money for positions are increasingly provi<strong>de</strong>d by contracts, see below.)<br />
This also means that LAOG has a responsibility in graduate studies, the teaching being provi<strong>de</strong>d by professors<br />
via the “Formation and Research Unit” (UFR) in Physics. LAOG is also heavily involved in the UJF<br />
administration and management of teaching: one of its members (Prof. C. Kahane) is leading the reform team<br />
for un<strong>de</strong>rgraduate studies at UJF Presi<strong>de</strong>ncy level, another (Prof. G. Henri) is responsible for the graduate<br />
studies in astrophysics at the Physics UFR (which, among others, provi<strong>de</strong>s many of the LAOG PhD stu<strong>de</strong>nts).<br />
UJF is an active partner also in LAOG research, in particular for <strong>de</strong>velopments in interferometry. It has<br />
provi<strong>de</strong>d a large competitive grant in 2003 (“BQR”, or “Bonus Qualité Recherche”) for optical fiber feeds, and<br />
is a strong supporter of a new project (referred to as “INTERPHAST”), set to occupy in the 2007-2008 time<br />
frame a large area (nearly 2000 m 2 in all) in the CERMO building adjacent to LAOG and IRAM. This project<br />
(mainly fun<strong>de</strong>d by the Rhône-Alpes region: 1.5 ME) inclu<strong>de</strong>s:<br />
• (i) the creation of a LAOG-IRAM European Center of Expertise for Interferometry in Astronomy (CEXIA),<br />
a scientific data analysis center based around the VLTI/JMMC for LAOG on the one hand, and the ALMA<br />
Regional Center project for IRAM, on the other;<br />
• (ii) a new Campus Center for Intensive Computing, extending the one already existing and currently hosted<br />
by LAOG (used not only by LAOG astrophysicists but by other researchers on campus in need of high-speed<br />
and massive computing, especially on grids);<br />
• (iii) a new “Joseph-Louis Lagrange Center for Physics and Astrophysics” for workshops and international<br />
collaborations (inspired by the Lorentz Center in Lei<strong>de</strong>n or ISSI in Bern).<br />
LAOG also has ties at various levels with other laboratories and institutes in the <strong>Grenoble</strong> area: INPG,<br />
IMEP, CEA-LETI etc. for instrumental research, LPSC and CRTBT for astroparticle physics and cosmology<br />
(“CosmAlp” collaboration). Without going into <strong>de</strong>tails, suffice it to say that LAOG is fully conscious of<br />
the richness of the technological and scientific environment of the <strong>Grenoble</strong> area, and seizes every significant<br />
opportunity of local collaborations or knowledge transfer, including towards the industry (see below).<br />
1.3.4 The European dimension of LAOG<br />
LAOG members are obviously involved in many international scientific collaborations (see <strong>de</strong>tails in the team<br />
parts III to VI) . In this section, we want to emphasize the ever growing involvement of LAOG in European<br />
programs and collaborations, first at a “traditional” institutional level (through large agencies like ESO and,<br />
to a small extent so far, ESA, see <strong>de</strong>tails in the team reports), but mostly, and increasingly, with the European<br />
Commission “Framework Programs” (FP).<br />
This is illustrated by the following evolution. When the previous report started (1999), LAOG was a no<strong>de</strong><br />
of a 7-laboratory FP5 “Research and Training Network” (RTN), entitled “Structure and Evolution of Young<br />
Stellar Clusters”. This RTN en<strong>de</strong>d in 2003. The main scientific objective was to gather a significant part of<br />
the European expertise in star formation, and bring together researchers and stu<strong>de</strong>nts spanning all the range<br />
of activities: observations, theory, numerical simulations, etc. (For reference, this network hired 11 post-docs<br />
29
and published 95 papers in four years.)<br />
Currently, un<strong>de</strong>r FP6, LAOG is a no<strong>de</strong> for two RTNs (“JetSet” and “Molecular Universe”) and a recently<br />
approved “Large Infrastructure” network (“Arena”, or “Astronomical Research Network in Antarctica”). In<br />
brief:<br />
• JetSet (Jet Simulation, Experiment, and Theory; PI T. Ray, Dublin.) This RTN (2004-2007) aims at<br />
a better un<strong>de</strong>rstanding of the physics of jets from young stars. Its originality stems from the fact that it<br />
brings together researchers that never worked together before: astronomers (observations), theoreticians (plasma<br />
experts), numericists, and experimentalists in fluid dynamics. All three thematic teams of LAOG have members<br />
in this network; its activities will be <strong>de</strong>scribed in more <strong>de</strong>tail in the FOST part.<br />
• Molecular Universe (PI X. Tielens, Groningen.) This RTN (2004-2007) brings together astronomers,<br />
mo<strong>de</strong>lists and experimentalists, as well as astrochemistry theoreticians, to better un<strong>de</strong>rstand the physics and<br />
chemistry of the <strong>de</strong>nse interstellar medium, all the way from molecular clouds to protostellar collapse and<br />
protostars. With its specific composition of experts both in mm-wave astronomy and theoretical chemistry, the<br />
Astromol team will bring a strong input into this network (see the Astromol part).<br />
• ARENA (Astronomy Research Network in Antarctica; PI N.Epchtein, Nice) This is a so-called “Large<br />
Infrastructure” network (2005-2008), with the goal of investigating the possibility to conduct intermediate- to<br />
large-scale astronomical projects using the French-Italian permanent scientific station “Concordia” at Dome C.<br />
LAOG is interested by the possibility to contribute to a medium-size interferometer. More <strong>de</strong>tails are given in<br />
the GRIL chapter.<br />
LAOG is also involved at high level in three “Joint Research Activities” (JRA) of “Opticon”, a large<br />
European, EC-fun<strong>de</strong>d collaboration:<br />
(i) adaptive optics (JRA1, Project Scientist: J.-L. Beuzit);<br />
(ii) interferometry (JRA4, PI: A. Chelli);<br />
(iii) <strong>de</strong>tectors (JRA2, PI: Ph. Feautrier).<br />
These JRAs are also <strong>de</strong>scribed in more <strong>de</strong>tail in the GRIL part.<br />
Within FP6, LAOG is again competing for a post-Young Stellar Clusters 12-laboratory RTN (“Constellation”;<br />
PI M. McCaughrean, Exeter), and will also compete for new Opticon funding (“Key Technologies for<br />
Astronomy”) in FP7 (starting in 2007).<br />
In addition to these network activities, which bring post-docs (RTNs) and a very significant funding (JRA),<br />
LAOG has a long-standing partnership with ESO (<strong>de</strong>livery of major instruments for the VLT), and with CNES<br />
and ESA (R&D contracts for Darwin, see <strong>de</strong>tails in the GRIL part; high-level involvement in the guaranteed<br />
time program of Herschel, see <strong>de</strong>tails in the Astromol part).<br />
1.3.5 Publicizing LAOG’s research: outreach and patents<br />
Part of our web site is accessible to the general public. But this is just the tip of the iceberg, and LAOG is<br />
very active in promoting astronomy to a wi<strong>de</strong> audience. Among the various public outreach actions un<strong>de</strong>rtaken<br />
these last few years, we can mention the following:<br />
• Actions in the LAOG building: weekly night observing sessions with our 40-cm telescope on its domed-roof,<br />
first initiated by Manuel Forestini), regular visits of the lab by high-school stu<strong>de</strong>nts;<br />
• Actions within OSUG: For promoting astronomy to a wi<strong>de</strong> audience, the collaboration with other laboratories<br />
of OSUG is very efficient and many actions have a common organization. For example, this is<br />
the case of the ”Fête <strong>de</strong> la Science”, organized each year in October at a single location for all OSUG<br />
activities.<br />
• Actions on the UJF campus: construction of the “Sentier Planétaire” (the Planetary Path), a scale mo<strong>de</strong>l<br />
of the solar system on the ground a few hundred meters in size (also initiated by Manuel Forestini);<br />
30
organization of astronomy events like the transit of Venus in June 2004 which attracted ∼ 2,000 visitors<br />
and featured an Internet link to New Zealand projected on a wi<strong>de</strong> screen; contribution to a laser version<br />
of the Fizeau experiment for measuring the speed of light, in the framework of the World Physics Year<br />
’05;<br />
• Actions on a national scale: public conferences by various LAOG members, interviews, consulting for<br />
popular astronomy journals, etc.<br />
LAOG’s research is also beneficial for the industrial world. In the past years, we have <strong>de</strong>posited five patents:<br />
• ”Dispositif d’actionnement électrostatique miniature et installation comprenant <strong>de</strong> tels dispositifs”, European<br />
Patent, CNRS/CEA, FR0206293 from 23/05/2002. Patent hol<strong>de</strong>rs: J. Charton and E. Stadler.<br />
• ”Composant MEMS électrostatique permettant un déplacement vertical important”, French patent, CNRS/CEA,<br />
FR0351211 from 26/12/2003. Patent hol<strong>de</strong>rs: J. Charton and C. Divoux (CEA/LETI).<br />
• ”Miroir déformable magnétique”, French Patent, CNRS, FR0452342 from 12/10/2004. Patent Hol<strong>de</strong>rs:<br />
J. Charton, Z. Hubert, L. Jocou, E. Stadler, P. Kern and J.-L. Beuzit.<br />
Two applications are currently procee<strong>de</strong>d in the frame of our activities on future <strong>de</strong>tectors:<br />
• ”Détecteur et caméra spectroscopique interférentiels”, French Patent, UJF INPI 04/52992, applied December<br />
15th 2004. Patent Hol<strong>de</strong>rs: le Coarer, E., Benech, P.<br />
• ”Spectrographes à on<strong>de</strong> contra-propagative”, French Patent, UJF INPI 05/08429, applied August 8th<br />
2005. Patent Hol<strong>de</strong>rs: le Coarer, E., Benech, P., Blaize, S., Kern, P., Léron<strong>de</strong>l, G., Morand, A.<br />
More <strong>de</strong>tails are given in the GRIL part.<br />
1.4 Budget: resources<br />
LAOG’s operating budget resources can be broken down in five sources, for a total of ∼ 400 − 500 kE/yr. Their<br />
respective contributions are illustrated graphically in figure 1.7 for the period 2001-2005. We now comment<br />
these funding sources in turn.<br />
• “Recurrent” funds, i.e., operating budget from the Ministry of Education and CNRS, on a four-year<br />
basis (the “quadriennal contract”). 3 As figure 1.7 shows, in rough terms this funding accounts for about<br />
half of the total operating budget, so it is a very important contribution that should be a<strong>de</strong>quately adjusted<br />
to the laboratory <strong>de</strong>mographic evolution. Over the 2002-2005 period, this has in fact been approximately<br />
the case (∼ 20% increase).<br />
• “Specific” budget, mainly from CNRS but also UJF (competitive “BQR” = Bonus Qualité Recherche).<br />
Basically, this budget follows that of the Ministry of Education, but sometimes one can obtain exceptional<br />
dotations (boost for a newly accepted project, replacement of an old laboratory car, etc.). It is mainly<br />
used for R& D activities, i.e., it is an investment corresponding to the scientific policy of LAOG to <strong>de</strong>velop<br />
research for future instruments which are not yet fun<strong>de</strong>d, by <strong>de</strong>finition. This line has fluctuated by more<br />
than a factor 2 (between 75 kE and 180 kE) <strong>de</strong>pending on the circumstances: for instance the largest<br />
amount corresponds to a UJF BQR of 60 kE in 2004.<br />
3 Note for our foreign members of our Visiting Committee. The level of funding results from the conclusions of the Evaluation<br />
Committee (the present exercise). It is based on a sum per capita (permanent researchers only; publishing engineers and nonpermanent<br />
staff like stu<strong>de</strong>nts of post-docs are not taken into account), which is calculated on the basis of publications, times a<br />
certain coefficient reflecting the quality of the laboratory, and is ultimately negotiated between the Ministry of education and the<br />
local university, UJF in our case.<br />
31
• National astronomy programs. 4<br />
Figure 1.7: Budget resources structure<br />
The main programs of interest for LAOG are PNPS (Programme National <strong>de</strong> Physique Stellaire), PNP<br />
(Programme National <strong>de</strong> Planétologie), and PCMI (Programme National <strong>de</strong> Physique et Chimie du Milieu<br />
Interstellaire), along with the GDR (research cluster) PCHE (Physique <strong>de</strong>s sources Cosmiques à Haute<br />
Energie) and the ASHRA (Action Spécifique pour la Haute Résolution Angulaire). The corresponding<br />
funds are used essentially for collaborative purposes (in some cases also for equipment), mainly, though<br />
not exclusively, within the French community. A yearly AO is issued, followed by a selection of proposals<br />
by a scientific committee.<br />
The funds ma<strong>de</strong> available through National Programs bring about 20 to 30 kE, (with fluctuations since<br />
the funding of the National Programs is itself variable). They can provi<strong>de</strong> very useful “pocket money”<br />
to the teams for collaborations (∼ 10-15% of the total LAOG operating budget). For their parts, LAOG<br />
teams are regularly successful, and use these funds as much as possible to have an in<strong>de</strong>pen<strong>de</strong>nt budget<br />
which they manage by themselves, mainly for scientific collaborations, including short-term visitors, and<br />
thematic workshops.<br />
This year (2005) a new national research funding structure has emerged, the “Agence Nationale <strong>de</strong> la<br />
Recherche” (ANR). Basically, this structure (endowed with about 700 ME in total), more or less inspired<br />
by the NSF, is meant to provi<strong>de</strong> funds and human resources (which is a major difference with national<br />
programs) on a competitive basis. While most of the funding is targeted towards major national priorities<br />
(e.g., nanotechnology projects), a fraction (about 20 %) is “open”. ANR issued its first AO last spring,<br />
and LAOG has submitted several proposals in the open category, mostly for post-docs (a critical <strong>de</strong>ficiency<br />
of the French research system). Thus the funding LAOG competes for with ANR is roughly an or<strong>de</strong>r of<br />
magnitu<strong>de</strong> larger than for programs –which is logical since salaries are now counted. We are expecting<br />
the results of this new experience, which could have a strong impact on our future funding.<br />
4 Another note for our foreign colleagues. French research in astronomy is structured into “national programs” or smaller-sized<br />
“research clusters” and “specific actions”, fun<strong>de</strong>d mainly by CNRS, with contributions from other state agencies like CNES (French<br />
space agency) and CEA (Atomic energy commission).<br />
32
• Contract-related funding. These funds are obtained as a result of successful proposals after an AO<br />
has been issued: these can be contracts with an international institute (like ESO), or with industry (e.g.,<br />
Alcatel Space). In some cases, after the contract is awar<strong>de</strong>d, an additional contribution (typically from<br />
CNRS/INSU) can be obtained, for instance if there was a share of the costs between the international<br />
institute and the country of the successful proposer (e.g., VLT instrumentation). These contributions are<br />
known respectively as “Contracts” and “Operations” .<br />
However, care must be taken in entering these funds into the laboratory budget. In<strong>de</strong>ed, a contract, by<br />
construction, is a box in which funding comes for a specific purpose: it is spent for that purpose only (for<br />
instance to buy equipment or instruments), and only overheads can be used to contribute to the operating<br />
budget of the laboratory as a whole (furniture, missions, etc.). For such contracts, LAOG typically retains<br />
10% of their amount for this purpose. It is this “tax” that must be ad<strong>de</strong>d to the previous funds, not the<br />
amount of the contract itself. (One should add for completeness that some contracts do inclu<strong>de</strong> salaries,<br />
but this is currently more the excpetion than the rule, and in view of the present budget exercise the<br />
salaries have not been taken into account for the sake of clarity.)<br />
Therefore, in figure 1.7 we have inclu<strong>de</strong>d only these 10% (referred to as “contributions” in the figure),<br />
and not the full amount of the “Contracts” and “Operations” (which is thus simply 10 times larger). As<br />
a result, and contrary to what might naively think, even though the contracts themselves may look large,<br />
(like 350 kE for WIRCAM at CFHT), the total amont effectively usable for LAOG common expenses is<br />
not so large (30-70 kE/yr, i.e., less than “specific” funds, or ∼ 15-20% of the budget).<br />
In this way one arrives at a realistic operating budget, comprised between 400 and 500 kE/yr. (If contracts<br />
are used fully instead, one obtains an enormous year-to-year vartiation: 1200 kE in 2004 vs. 650 kE in 2005,<br />
which obviously does not reflect at all the way the laboratory operates on a day-to-day basis.) This is perhaps<br />
the good news. The bad news is that when one divi<strong>de</strong>s this amount by the LAOG population, one gets a very<br />
significant <strong>de</strong>crease of funding as a function of time. This is illustrated in figure 1.8, which displays two parallel<br />
histograms. The histogram with the largest boxes shows the operating budget per capita if one counts only the<br />
permanent staff (36 in 2001, 43 in 2005), the smaller boxes if one counts the whole population effectively present<br />
(i.e., including PhD stu<strong>de</strong>nts, post-docs, etc.: 76 in 2001, 98 in 2005). The figure also displays a regression line<br />
for the two histograms: the <strong>de</strong>cline is obvious, on the or<strong>de</strong>r of 20% over five years (more like 30% if one takes<br />
inflation into account), with admittedly fluctuations on the or<strong>de</strong>r of 10% due to start and end of contracts.<br />
Figure 1.8: Time evolution of the operating budget per person (in kE). Large box histogram: counting permanent<br />
staff only. Small box histogram: counting all LAOG members (including PhD stu<strong>de</strong>nts, post-docs, etc.).<br />
Pending a new way of operating with the ANR in the future, the most obvious solution would be to look<br />
for more contracts. But this is misleading: (i) doubling the amount of contracts would bring not more than<br />
another 10 %, and only to 15-20 % of the operating budget ; (ii) more importantly, LAOG basically has one or<br />
two large contracts per “quedriennal”, corresponding to the instrument plans of agencies like ESO, and this is<br />
the best it can hope for given its mission to do fundamental research, and not look for large-scale applications.<br />
The other solution is to reinforce significantly the “recurrent” funding, since, as noted before, it amounts to<br />
about half of the LAOG operating budget.<br />
33
1.5 From dreams to reality: Human resources<br />
Contrary to the funding situation, LAOG has been fortunate in getting a significant number of permanent<br />
positions for researchers, while the ITA population has remained stable (22). Over the 2002-2005 period, LAOG<br />
had 3 fresh CNRS positions, 2 astronomers, and 1 UJF assistant professor (unfortunately just compensating<br />
for the loss of M. Forestini). Overall, LAOG remains a young laboratory, not only because of a comparatively<br />
recent creation, but also because of the number of young researchers and engineers.<br />
This is testified by the <strong>de</strong>mographics (see figure 1.9): the average age of permanent researchers is 44,<br />
while, even more remarkably, the average age of engineers and technicians is 40. In passing, we note that as a<br />
consequence most of the actors of the present prospective exercise will be able to conduct the proposed projects,<br />
even very long-term ones, themselves if they want to. This is a truly fortunate situation among similar-sized<br />
laboratories in France.<br />
Figure 1.9: LAOG age histogram<br />
Another asset of LAOG is its Technical Group, hea<strong>de</strong>d by P. Kern. Operationally distinct from GRIL, but<br />
sharing with it all of its engineers (14), backed by 6 assistant-engineers and technicians, this Group has the<br />
major responsibility to build instruments and make them work and used by the community. Its role is illustrated<br />
in the new LAOG histogram (see Figure 1.3). More <strong>de</strong>tails on its structure and internal organization are given<br />
in Appendix in chapter 18, and its impressive record in building instruments for ESO and CFHT, is <strong>de</strong>scribed<br />
in the GRIL part.<br />
1.6 The 2007-2010 prospective and beyond<br />
1.6.1 Main scientific objectives<br />
Any scientific prospective spanning a rather long period (2007-2010 is just a step towards a longer term future)<br />
is a somewhat risky exercise because on many unknown external factors. Most importantly for LAOG, future<br />
projects of major agencies like ESO or ESA and their funding inclu<strong>de</strong> highly political factors like the <strong>de</strong>velopments<br />
and future science priorities in France and in Europe, but we can at least <strong>de</strong>scribe LAOG’s objectives<br />
given the current general context.<br />
The present structure of LAOG in four teams has, among others, the advantage of allowing to streamline<br />
the main scientific issues and questions. Given the expected progress and projects, these can be synthesized as<br />
follows.<br />
• From local to global star formation. A major topic will remain the formation of solar-type stars,<br />
34
in relation with planet formation. Currently unsolved problems involve the exact nature of gravitational<br />
collapse: what is the leading factor, magnetic fields or turbulence ? The physico-chemistry of protostellar<br />
envelopes and young protoplanetary disks, with a whole array of spectral diagnostics down to the innermost<br />
regions (< 1 AU), will give us precious indications about the velocity field and extent of the accretionejection<br />
phenomenon, the <strong>de</strong>nsity and temperature conditions, the existence and abundance of possible<br />
prebiotic molecules, etc. The advent of Herschel (to be launched in early 2008) will allow LAOG to<br />
attack these questions with sophisticated chemistry and radiative transfer mo<strong>de</strong>ls to i<strong>de</strong>ntify and interpret<br />
thousands of spectral lines. ALMA will later expand the result at high spectral resolution; however the<br />
spectral line diagnostic will be unable to inclu<strong>de</strong> the lines that are un<strong>de</strong>tectable from the ground. Currently,<br />
ALMA is not expected to be operational before 2012, so within the current prospective a major effort will<br />
be <strong>de</strong>voted by the Astromol team to the interpretation of Herschel data, while increasing the involvement<br />
in existing facilities like the IRAM telescopes (single-dish 30m and PdBI interferometer), JCMT and<br />
CSO in Hawaii, APEX in Chile (a precursor to ALMA antennae). A complementary view, mainly for<br />
comparison with the early solar system, will be offered by the laboratory study of irradiation effects by<br />
high-energy photons and particles emitted by the central protostar.<br />
At later stages, other issues related to global star formation emerge, also on the FOST si<strong>de</strong>: e.g., why is it<br />
that star formation occurs in cluster mo<strong>de</strong> and in isolated mo<strong>de</strong>; more generally in so many different mo<strong>de</strong>s<br />
(including starbursts in galaxies for instance); what is the origin of brown dwarfs, and in particular of the<br />
“free-floating” low-mass objects far from star-forming regions ? To what extent is the IMF universal ?<br />
The FOST teams attacks some of these problems with mo<strong>de</strong>rn tools like N-body simulations and exten<strong>de</strong>d<br />
surveys at CFHT like CFH12K and WIRCAM KP surveys of young open clusters, or exten<strong>de</strong>d nearby<br />
star-forming regions like Taurus.<br />
• Disk evolution and planet formation. One of the most exciting challenges of mo<strong>de</strong>rn astronomy,<br />
with many <strong>de</strong>ep implications like the universality of life, is to know whether the solar system is typical or<br />
exceptional among all planetary systems. Two different approaches can be consi<strong>de</strong>red.<br />
(i) On the one hand, to un<strong>de</strong>rstand whether and how planets (especially terrestrial planets) form as the<br />
ultimate phase of evolution of circumstellar disks around young, solar-type stars. This requires an in<strong>de</strong>pth<br />
study of the evolution of disks, from their young stages dominated by accretion and correlated jets,<br />
to later stages where dynamical interactions (instabilities, companions, etc.) <strong>de</strong>eply affect the growth of<br />
dust grains into planetesimals and planets, over timescales of ∼ 10-100 Myr. While LAOG currently is<br />
not directly involved in the study of planet formation per se, it is certainly in an enviable place to obtain<br />
constraints on prevailing physical conditions, and on the history of disk structure evolution (gaps, rings,<br />
spirals, etc.) from observations and mo<strong>de</strong>ls.<br />
(ii) The other approach is to consi<strong>de</strong>r already formed exoplanetary systems. With a sufficiently large<br />
sample (hundreds ?) of planetary systems down to the lowest possible planetary masses (Earthlike,<br />
i<strong>de</strong>ally), one can start to apprehend the rules and the exceptions, in comparison with our solar system.<br />
The current arsenal of exoplanetary search consists of a majority of radial-velocity (stellar reflex motion)<br />
<strong>de</strong>tection (30 of them have a LAOG member as co-discoverer), and of a handful of transits in front of<br />
the host star. Apart from the only confirmed (so far) recent <strong>de</strong>tection of a planetary mass object around<br />
a brown dwarf (a situation hardly comparable to the solar system), no direct imaging of exoplanets is<br />
currently available. The <strong>de</strong>velopment of instruments able to bridge this gap will open an entirely new<br />
era –if only because systems with orientations at large angles to the line of sight will become <strong>de</strong>tectable,<br />
significantly enriching the parameter space for exoplanetary systems and putting new constraints on their<br />
origin.<br />
With the Astromol and FOST teams, LAOG has the expertise to have these two ends meet and study<br />
how well (or how badly) these two approaches may converge, in particular with the new instrumental<br />
projects (see below) it is leading. In short, at the horizon 2010 LAOG hopes to make radical advances in<br />
our current un<strong>de</strong>rstanding of star and planet formation, with the ultimate goal to pin down the connection<br />
(or lack thereof) between exoplanetary systems and our solar system.<br />
• The close environment of accreting objects, from black holes to young stars. As its core activity,<br />
over the term of the present prospective (2010) the SHERPA team will focus on the physical processes that<br />
take place in the close environment of Black Holes. This inclu<strong>de</strong>s the analysis of the gross phenomenon<br />
combining MHD and gravitation, to high energy radiation and astroparticle physics, via the turbulent<br />
transport theory and the kinetic theory of relativistic plasmas and particle acceleration. These theoretical<br />
<strong>de</strong>velopments will be applied to various physical environments: the Blazar phenomenon (stratified mo<strong>de</strong>ls,<br />
variability); micro-quasars (“two-flow” paradigm, mo<strong>de</strong>lization of the changes of state); signatures of the<br />
Kerr metric in the phenomenology of AGNs and micro-quasars; instabilities and turbulent transport in jets<br />
35
and accretion disks with heavy numerical MHD simulations; and relativistic plasma physics: reconnections,<br />
shocks and flows (for Blazars, micro-quasars and Gamma Ray Bursts).<br />
Some branch activities will continue in parallel: accretion-ejection phenomena in young stellar objects<br />
(numerical simulations of the interaction between the stellar magnetosphere and the accretion disk);<br />
astrocladistics (innovative classification method of galaxies in relation with the issue of AGN formation<br />
by merging). Also, the team will continue <strong>de</strong>veloping connections with High Energy Experiments (XMM,<br />
INTEGRAL, GLAST, SIMBOL-X, HESS etc.) and with the LAOG observing facilities (VITRUV, ...).<br />
Over the longer term (2015), the Sherpas team expects to be involved in the theory of transitory signals<br />
from Black Hole environments that will be recor<strong>de</strong>d simultaneously by different kinds of astroparticle<br />
experiments, revealing different but correlated aspects of their phenomenology. This will involve gammaray<br />
transient emissions, neutrino bursts and gravitational waves. The main sources of such combined<br />
events will be the double quasars. The Pierre Auger Observatory for UHE cosmic rays will also be an<br />
important source of informations for AGNs and GRBs physics, as well as for the knowledge of the cosmic<br />
magnetic field.<br />
• Instrumental <strong>de</strong>velopments: towards higher angular resolution and higher dynamic range.<br />
The instrumental activities for the present period have been dominated by the <strong>de</strong>livery of two major<br />
NIR (JHK) instruments for ESO’s VLT: the large adaptive optics system NAOS, and the interferometric<br />
recombiner AMBER, as well as the WIRCAM wi<strong>de</strong>-field NIR camera for CFHT. While these instruments<br />
are already successfully working, they show that the present goals of LAOG cannot be fully obtained<br />
with them: if one wants to really un<strong>de</strong>rstand the formation of planetary systems, one needs to reach a<br />
linear resolution of 1 AU or less at 150 pc (the typical distance of low-mass star forming regions), which<br />
translates in a 6 mas spatial resolution; if one wants to image planets close to their host star, i.e., within<br />
the first diffraction minimum, a tremendous dynamic range is required (∼ 10 −6 ).<br />
To face these challenges, LAOG has embarked in two major projects for ESO’s 2nd generation of VLT<br />
instruments, which will draw the majority of its engineering manpower (15 FTE) for the period 2007-2010:<br />
• (i) The VLT-PF (“Planet Fin<strong>de</strong>r”) project, which is now in the final stages of approval. LAOG<br />
led a European consortium which was selected by ESO in 2005 over a competing one. Compared to NAOS,<br />
the main emphasis is on a very high dynamic range (∼ 3 × 10 5 at 1 Airy radius, or at ∼ 20 mas at 1 µm for<br />
an 8-m telescope), to reach the scientific goal of direct <strong>de</strong>tection of dozens of Jupiter-mass planets, possibly in<br />
multiple systems (as a few are already known from the radial-velocity method). It is expected to be completed<br />
in 2009-2010. This will pave the way to future spectroscopy of these planets, and eventually of Earth-like planets<br />
(Darwin project, post-2015, see below).<br />
• (ii) The VITRUV project. Proposed to ESO which may reach a <strong>de</strong>cision in 2006, this is currently<br />
an in-house LAOG project for the 2nd generation VLTI. It basically consists in a large interferometric beam<br />
recombiner making use of integrated optics. Its ultimate goal is to use all 8 Paranal telescopes (4 UT and 4 AT)<br />
to make up one of the world’s largest optical/IR interferometer, with a maximum baseline of 200 m. This will<br />
allow to reach the maximum possible angular resolution of ∼ 0.5 mas in the visible range, allowing for instance<br />
to probe the inner regions and fine structure of circumstellar disks of young stars and AGNs and their jets, i.e.,<br />
to probe in unprece<strong>de</strong>nted <strong>de</strong>tail the “central engine” of the accretion-ejection phenomenon in a wi<strong>de</strong> diversity<br />
of environments.<br />
Therefore, the main challenge for LAOG resources will be to manage two important projects (if VITRUV<br />
is approved) over the same time frame, while continuing R&D activities. Details about other projects un<strong>de</strong>r<br />
consi<strong>de</strong>ration can be found in the GRIL chapter.<br />
To help in the interpretation of increasingly complex observations, LAOG is also investing significant efforts<br />
to contribute to the Virtual Observatory (VO). In its present stage, the VO offers an easy and interoperable<br />
access to the astrophysical data (spectra, images, etc) gathered by the major observatories all over the world<br />
and to the corresponding publications and tables. This huge work is the fruit of an unprece<strong>de</strong>nted international<br />
collaboration, through a hierarchy of working groups and institutions – with special mention in France to the<br />
CDS in Strasbourg and to the recent “Action Spécifique Observatoire Virtuel” of INSU. Our objective is to<br />
enrich the VO with original services. Most tools <strong>de</strong>veloped at the JMMC (as already done for SearchCalib)<br />
will be interwoven to the VO for an optimal preparation and calibration of observations. Also, theoretical<br />
<strong>de</strong>velopments will be offered to the VO. Inelastic collisional rates computed in the ASTROMOL team (including<br />
the corresponding milestones for the “Molecular Universe” RTN framework) will be inclu<strong>de</strong>d in the advanced<br />
36
BASECOL database hosted in Meudon to feed line data analysis requests with the latest data. Corresponding<br />
simple and pedagogic VO services (e.g. at LVG level) will be <strong>de</strong>veloped for the non specialist user with error<br />
bars and warnings.<br />
1.6.2 Long-term strategic questions for LAOG<br />
The world’s astronomical panorama is evolving fast, and long-term instrumental projects are already at the<br />
discussion or even R&D stage. LAOG has already been contacted to participate in some of these projects.<br />
The main challenge for LAOG is to keep in focus its scientific goals, and to give a weighted priority to its<br />
participation to any long-term project <strong>de</strong>pending on how these goals may be fulfilled. While, as we have seen<br />
at length, LAOG has <strong>de</strong>finite projects for the 2007-2010 time frame, it also has to consi<strong>de</strong>r them within a<br />
longer-term perspective, out to 2015 or even beyond.<br />
While the list of opportunities may evolve, and no <strong>de</strong>finite <strong>de</strong>cision can be taken now, the current strategic<br />
issues un<strong>de</strong>r discussion at LAOG are the following.<br />
• Extremely Large Telescopes. There are several studies around the world to dramatically increase<br />
the size of current telescopes by use of segmented mirrors. ESO, for its part, is pushing the OWL<br />
(“OverWhelmingly Large”) telescope project. The target diameter is 100m, but feasibility studies may<br />
reduce it to 30m. Whereas cosmologists push towards the largest possible sizes in or<strong>de</strong>r to collect photons<br />
from the youngest possible galaxies, recent studies seem to indicate that beyond a diameter of 30m no<br />
significant gain (in terms of a sensitivity vs. contrast compromise) can be expected for exoplanet science.<br />
However, should the larger size be <strong>de</strong>ci<strong>de</strong>d, there are i<strong>de</strong>as (in particular within LAOG) to use selected<br />
mirrors of an ELT to make up an interferometer within the telescope itself, with an unprece<strong>de</strong>nted, almost<br />
continuous coverage of the uv plane.<br />
• Astronomy in Antarctica. The fact that the French-Italian Concordia scientific station has recently<br />
been completed at Dome C has given a boost to astronomical projects in Antarctica. Located <strong>de</strong>ep<br />
within the Antarctic plateau, at 3200m altitu<strong>de</strong> in a very dry and stable atmosphere, Concordia is able<br />
to provi<strong>de</strong> a permanent logistical support, even in winter, for a dozen scientists of all disciplines. LAOG<br />
participates in a recently approved EC-fun<strong>de</strong>d “Large Infrastructure” FP6 project (ARENA, see above),<br />
which aims at investigating in <strong>de</strong>tail the feasibility of establishing a European astronomy facility, including<br />
an interferometer, at Dome C. Up to now, LAOG is involved mo<strong>de</strong>stly, mostly for scientific support (for<br />
instance, a question to address: is Dome C a better location than Paranal for star and planet formation<br />
issues ?). The rumours according to which ESA is currently studying the i<strong>de</strong>a of putting the GENIE pre-<br />
Darwin nulling interferometer at Dome C rather than at Paranal, un<strong>de</strong>r an adapted form (ALLADIN),<br />
may change the situation: in view of its current involvement in Darwin R&D studies (see below), LAOG<br />
is ready to adopt the view that, in addition to doing its own science with it, an ALLADIN-type project<br />
can in<strong>de</strong>ed be an important step towards a major space interferometer like Darwin. This will however<br />
require extra manpower not currently available.<br />
• Going out to space ? Darwin. This is an ESA “Horizon 2000+” program cornerstone. It will not<br />
fly before 2015. Its primary scientific goal is extremely ambitious and difficult: to find evi<strong>de</strong>nce for<br />
extraterrestrial life by <strong>de</strong>tecting ozone lines (the currently accepted major tracer of life) on Earth-like<br />
planets. This will be done with a 4-spacecraft nulling space interferometer (3 in<strong>de</strong>pen<strong>de</strong>nt telescopes and<br />
a recombiner, the whole array being controlled by laser beams), i.e., blocking with an extreme efficiency<br />
(contrast of ∼ 10 −9 ) the light of the central star. This is arguably a formidable technological and scientific<br />
challenge. While LAOG does not yet have its own expertise in exoplanetary atmospheres (drawn elsewhere<br />
from solar system planetary and brown dwarf atmospheres), it is clear that it already has a strong longterm<br />
scientific interest in Darwin. It has already manifested this interest by participating to the scientific<br />
group of “Pégase”, a Darwin precursor space interferometer proposed to CNES, currently in competition<br />
for a pre-Phase A study. The ozone lines to be <strong>de</strong>tected being in the mid-IR range, it is critical for Darwin<br />
to be able to recombine beams in this wavelength range. The recent result obtained by LAOG, after several<br />
years of research un<strong>de</strong>r ESA/CNES/industrial R&D contracts, to gui<strong>de</strong> 10 µm waves for the first time,<br />
represents a breakthrough towards building a recombiner for Darwin. LAOG is seriously consi<strong>de</strong>ring<br />
boosting these instrumental efforts and will have, in parallel, to <strong>de</strong>velop collaborations and/or its own<br />
scientific expertise in planetary atmospheres in the next <strong>de</strong>ca<strong>de</strong>, to be able to reap for itself the scientific<br />
benefits of this exciting adventure. It is noteworthy that the present LPG prospective inclu<strong>de</strong>s a new<br />
37
emphasis on the chemistry of planetary atmospheres, with an explicit goal to be involved in exoplanetary<br />
atmospheres by 2010. While LPG is concerned on the short term with solar system objects (mostly Titan,<br />
in relation with the Cassini-Huygens mission), LAOG (Astromol and/or FOST) will have discussions<br />
about possible common scientific goals for exoplanets in the same time frame, in preparation for Darwin.<br />
• Other space missions ? Over the long term, LAOG may also consi<strong>de</strong>r a greater instrumental involvement<br />
in telescopes that can only be put in space, while keeping within its scientific priorities: high-energies,<br />
and submm astronomy. The projects that one can consi<strong>de</strong>r would be mostly with CNES or/and ESA.<br />
In the high-energy, hard X-ray domain, the Sherpas team is already involved (for AGNs and compact<br />
binaries) in the scientific group around Simbol-X, a two-satellite proposal led by CEA Saclay (which is<br />
competing, along with Pégase, for a CNES-fun<strong>de</strong>d pre-Phase A study), but no instrumental <strong>de</strong>velopment<br />
is currently foreseen at LAOG. In the 2015 timeframe, i.e., the same as Darwin, the XEUS project, successor<br />
to XMM, is the leading high-energy project within ESA. LAOG might be more involved in the project<br />
(which has strong support from space laboratories in France), but again likely not at the hardware level.<br />
In the submm domain of interest mainly for Astromol, Herschel, to be launched in 2007, will require many<br />
years of scientific exploitation. Its only currently i<strong>de</strong>ntified long-term successor in ESPRIT, but with no<br />
date set for launch. On the other hand, there are already also here some thoughts about Antarctica (the<br />
most interesting domain is the THz range). Here again, there are no current plans for a LAOG hardware<br />
involvement, but it has to stay alert to possible evolutions.<br />
1.7 Conclusions: A vision for the post-2010 future of LAOG<br />
By 2010, because of the important scientific results it has already obtained, and its successful bids to build new<br />
major instruments for the VLT, it can reasonably be expected that LAOG will have the following ambitious<br />
objectives for the next <strong>de</strong>ca<strong>de</strong>. But it has to grow again to accomplish them...<br />
• The VLT-PF and, hopefully, VITRUV will be completed and start operations at the VLT. This means<br />
that in the mean time, most of LAOG’s scientific results will be obtained with existing instruments,<br />
mostly at the VLT (with instruments it contributed to build or other Paranal instruments), and at CFH<br />
(exploitation of WIRCAM). A much better knowledge of the evolution of circumstellar disks, over a time<br />
span of ∼ 1 to ∼ 100 Myr, is expected from instruments like NAOS or AMBER. Along with work on the<br />
evolution of early solar system going on elsewhere (and at LPG in particular), the hope is that by 2010 we<br />
will know as much (or as little ?) about planet formation as we know about star formation today. Several<br />
hundreds of exoplanets, and possibly several tens of exoplanetary systems will be known, some containing<br />
Earth-like planets. Even though the VLT-PF has the main goal of imaging Jupiter-sized planets close to<br />
the host star, the recent images of the brown dwarf-exoplanet system 2M1207 <strong>de</strong>monstrate that several<br />
systems will certainly be imaged before the VLT-PF becomes available. On the other hand, studies will<br />
have matured at LAOG to contribute to building some kind of ELTs and/or single telescopes and possibly<br />
an interferometer in Antarctica, as well as contributing to the Darwin recombiner. The participation of<br />
LAOG to all these ventures will ensure activities of LAOG in the field of star and planet formation well<br />
into the next <strong>de</strong>ca<strong>de</strong>. But such ambitious goals require a significant increase in manpower in the coming<br />
years: 3-4 researchers for FOST, 3-5 engineers and technicians for GRIL and the Technical group.<br />
• The Herschel mission will be operational right into the present prospective, and thus, by opening a new<br />
window in the universe, will constitute the newest branch of submillimeter astronomy, with a rich harvest<br />
in spectroscopy and key results on star formation and early evolution. On the ground, IRAM telesscopes<br />
will play a pivotal role, at least until ALMA starts operations (hopefully in 2012), along with other existing<br />
(sub)millimeter telescopes elsewhere. Already a significant part of the astronomical activities related to<br />
star formation is <strong>de</strong>dicated to the search for prebiotic molecules, as part of a worldwi<strong>de</strong> effort to <strong>de</strong>velop<br />
exobiology. As explained in the pre<strong>de</strong>ding sections, the Astromol group is particularly well placed to<br />
pursue these lines of research. However, the task is daunting, and the Astromol team has to grow, and<br />
grow fast, since a few of its members will have retired by 2010. Hiring, and/or attracting at least 2-3<br />
permanent researchers in the coming years is absolutely vital for Astromol.<br />
• A (tentative !) picture appears from combining three factors towards 2010: (i) <strong>de</strong>velopment of exoplanet<br />
research in the FOST team; (ii) <strong>de</strong>velopments in the search for prebiotic molecules, and also in theoretical<br />
chemistry in the Astromol team; (iii) the planned <strong>de</strong>velopments in the chemistry of planetary and<br />
38
exoplanetary atmospheres at LPG. This picture is the emergence of what might be called (in analogy<br />
with cosmology): observational exobiology, i.e. obtainining astrophysical and astrochemical diagnostics<br />
for contraining the conditions for the emergence of life in other planetary systems. This would be an<br />
extraordinary preparation for LAOG (in addition to its possible instrumental <strong>de</strong>velopments) and LPG<br />
to be really involved in the scientific exploitation of the Darwin mission. This could conceivably lead<br />
to create at that time a new team: S2E (Science <strong>de</strong>s Exoplanètes et Exobiologie: Exoplanetary Science<br />
and Exobiology), possibly a joint venture of LAOG (researchers from FOST and Astromol ?) and LPG.<br />
(Close contacts with the CRAL group in Lyon, which is already very strong in brown dwarf and planetary<br />
atmospheres, should also be <strong>de</strong>veloped.)<br />
• On the high energy si<strong>de</strong>, the adventure is no less exciting. As explained in the Sherpa prospective, the next<br />
<strong>de</strong>ca<strong>de</strong> will see the coming of age of an entirely new generation of telescopes, opening non-electromagnetic<br />
windows on the universe: gravitational waves and neutrinos. This will be the time of a radically new<br />
approach to the physics of black holes. Already the Sherpa team is exploiting data from high-energy<br />
telescopes both on the ground (HESS) and in space (X-ray and γ-ray satellites). Theoretical <strong>de</strong>velopments<br />
will require to explore new fields of physics and involve more and more numerical simulations. The goal<br />
of the Sherpa team is to hire 2 researchers in the coming years. What is not clear at present (but we<br />
have some time to think about it) is whether the Sherpa team will keep the close ties it has today with<br />
the rest of LAOG and still invest part of its efforts in the (more conventional ?) physics of young stars<br />
and planets: its expertise in magnetic fields and plasmas could still to be the common ground.<br />
We started this report by emphasizing the youth and fast growth of LAOG. We hope the rea<strong>de</strong>r is now<br />
convinced that there is currently no reason to fear a “growth crisis”, and that LAOG will be able to be up to<br />
the scientific challenges it wants to take. In total, it strongly hopes to hire or attract 7 to 9 new researchers,<br />
and 3 to 5 new engineers and technicians by 2010. Unless there is a crisis in funding (as was nearly the case in<br />
2003), LAOG, in its local, national, and international environments, can only expect a bright long-term future.<br />
39
Part III<br />
TEAM ASTROMOL<br />
Sub-arcsecond image of a complex organic molecule in the proto-binary system of<br />
IRAS16293-2422<br />
41
Chapter 2<br />
Presentation and Scientific Objectives<br />
2.1 Presentation of Astromol: composition, goals and summary of<br />
activities<br />
The Astromol team was created in January 2003, with the new organization of the LAOG structure. It results<br />
from the merging of the group working on Theoretical Molecular Physics with the group working on Star<br />
Formation (born from the previous group<br />
on the Interstellar and Circumstellar Medium). Both groups are mostly newly formed, by accretion from<br />
different observatories and laboratories as well as by members originally from LAOG. Table 2.1 lists the staff<br />
members of Astromol: nine researchers, three of whom are teachers at UJF, one is Astronome at UJF, and five<br />
are CNRS/CEA researchers.<br />
Name Gra<strong>de</strong> Specialty<br />
J-J. Benayoun Professor UJF Astrophysical mo<strong>de</strong>ls<br />
C. Ceccarelli Astronome Astrophysical obs and mo<strong>de</strong>ls<br />
F-X. Desert a Astronome Astrophysical obs<br />
A. Faure CR2 Molecular Physics<br />
C. Kahane Professor UJF Astrophysical obs<br />
B. Lefloch CR1 Astrophysical obs and mo<strong>de</strong>ls<br />
T. Montmerle DR1 Astrophysical obs and mo<strong>de</strong>ls<br />
C. Rist Maitre <strong>de</strong> Conf. Molecular Physics<br />
P. Valiron DR2 Molecular Physics<br />
L. Wiesenfeld CR1 Molecular Physics<br />
Table 2.1: List of the permanent staff members belonging to the Astromol team and their respective expertise.<br />
a Note that Desert joined Astromol team during 2005: his activity is <strong>de</strong>scribed in §4.5.<br />
The goal of the Astromol team is the study of the physical and chemical proprieties of the inter-stellar and<br />
pre-stellar matter, by a tight coupling between the theoretical and observational approaches. One major goal<br />
for Astromol is the study of the chemical and physical evolution of solar type stars in the first phases of their<br />
formation: from the first steps leading to the gravitational collapse -Pre-Stellar Cores- to the proto-planetary<br />
disk phase.<br />
To achieve our goal:<br />
• we carry out observations at the large radio to sub-millimeter ground based telescopes, as well as space<br />
based telescopes in the FIR, NIR and X-rays wavelengths;<br />
• we <strong>de</strong>velop mo<strong>de</strong>ls to solve the line formation, radiative transfer and chemical composition problems;<br />
43
• we <strong>de</strong>velop quantum and classical formalisms in molecular physics, relevant to the un<strong>de</strong>rstanding of the<br />
physics and the spectra that we observe;<br />
• we compute theoretical molecular physics data, <strong>de</strong>veloping and using state of the art ab initio quantum<br />
chemistry co<strong>de</strong>s as well as dynamical calculations.<br />
Astromol is, therefore, composed of people having very different skills and backgrounds: astrophysical observations,<br />
astrophysical mo<strong>de</strong>ling, ab initio molecular calculations, and theoretical molecular physics. In the<br />
following we will refer to the two major activities of Astromol as the Star Formation and Molecular Physics<br />
respectively. Figure 2.1 shows the logical scheme of the interaction between the astrophysical and the molecular<br />
Figure 2.1: The activities of Astromol and the synergy of the different components. The logical sequence<br />
is as follows: 1- we select the target of our study; 2- we do observations of the target object; 3- by using<br />
the collisional coefficients relevant to the observed molecule, we interpret the observations <strong>de</strong>riving the temperature,<br />
<strong>de</strong>nsity and chemical composition of the studied object, by means of theoretical radiative transfer<br />
mo<strong>de</strong>ls; 4- by using the rates of the chemical reactions we build a chemical mo<strong>de</strong>l; 5- finally, we reconstruct the<br />
physics/dynamics/chemistry of the target of our study.<br />
physics expertise of Astromol members, taking the example of the study of a solar type forming star. In or<strong>de</strong>r to<br />
un<strong>de</strong>rstand the star formation process one needs to reconstruct the physical, dynamical and chemical structure<br />
of the matter, as function of time, namely as this structure evolves during the formation process. One of the<br />
best tools for this study are the lines emitted and/or absorbed by the gas, because:<br />
i) lines intensities (either in emission or in absorption) <strong>de</strong>pend on the gas temperature and <strong>de</strong>nsity, and, for this<br />
reason, multi-frequency line observations allow to reconstruct the <strong>de</strong>nsity and temperature profile of the gas;<br />
ii) lines from different chemical species allow to reconstruct the chemical composition of the gas;<br />
iii) lines profiles provi<strong>de</strong> information on the kinematics of the studied region.<br />
Given the involved temperatures (between 10 and few hundreds Kelvin) and <strong>de</strong>nsities (between 10 4 and 10 9<br />
cm −3 ), molecular lines are the privileged tool for studying forming solar type stars. The sequence in Fig. 2.1<br />
illustrates, in practice, the synergy between the astrophysical observations and mo<strong>de</strong>ling, and the theoretical<br />
molecular computations. Astrophysical observations and mo<strong>de</strong>ling motivate theoretical molecular computations;<br />
in turn, theoretical molecular computations feed the astrophysical mo<strong>de</strong>ling, and allow the correct interpretation<br />
of the data. In synthesis, the research activity of Astromol may be summarized into a few major axes:<br />
observations at telescopes (§2.2), <strong>de</strong>velopment of astrophysical mo<strong>de</strong>ls (§2.3), <strong>de</strong>velopment of molecular physics<br />
theories and co<strong>de</strong>s, plus computation of molecular and intermolecular properties (§2.4). Our research leads<br />
to several publications in international specialized journals, as well as to communications to congresses, both<br />
invited or not (§2.5).<br />
Another important aspect for Astromol is represented by the teaching and stu<strong>de</strong>nt formation, an activity<br />
which absorbs a substantial fraction of the team energy and time, and which is vital for the life of the team<br />
itself (§2.6).<br />
Finally, Astromol is actively involved in national and international activities and collaborations. It is worth<br />
here to mention three large national and international projects, where Astromol is a major actor (see §2.7<br />
for a <strong>de</strong>tailed <strong>de</strong>scription): “WAGOS”, “FP6 - THE MOLECULAR UNIVERSE”, and “HERSCHEL SPACE<br />
OBSERVATORY - HIFI”. Regarding the interaction with the “Programmes Nationaux” Astromol is financially<br />
44
supported by PCMI and PNPS, and members of Astromol have been and currently are members of the PCMI<br />
board.<br />
Table 2.2 summarizes the Astromol activities at glance.<br />
Observations at the telescopes Satellite: CHANDRA + XMM +<br />
SPITZER + ISO data reduction<br />
Ground-based: IRAM + JCMT + CSO...<br />
Development of astrophysical mo<strong>de</strong>ls Lines from collapsing envelopes<br />
and LVG co<strong>de</strong>s<br />
Molecular physics: theories and co<strong>de</strong>s Ab initio and collision co<strong>de</strong>s <strong>de</strong>velopment<br />
Transition state theory.<br />
Intensive computation on National Computer<br />
facilities and local Ciment network facilities<br />
Teaching and stu<strong>de</strong>nts formation 2 Professors + 1 MdC + 1 Astronome<br />
UJF-SD + Master 1 Physics<br />
5 PhD thesis + 5 DEA stages<br />
Publications and communications Articles in refereed Journals: 102<br />
Invited presentations in international<br />
congresses: 24<br />
Collaborations National: FOST, WAGOS, PCMI, PNPS...<br />
International: FP6 “The Molecular Universe”<br />
Herschel-HIFI and ALMA projects, JETSET<br />
Table 2.2: Astromol activities at glance for the period 2002-2005.<br />
2.2 Observations at the telescopes<br />
Astromol members carry out observations with satellite and ground based telescopes, covering a large frequency<br />
range, from the radio to the X-ray.<br />
Satellite telescopes: Astromol members (TM) are involved in the explotation of the two large X-rays telescope<br />
currently in orbit: Chandra and XMM. These facilities, launched in 1999, have allowed to conduct observations<br />
of star-forming regions in two directions: (i) characterization of the stellar X-ray sources, from massive stars to<br />
substellar objects (brown dwarfs: see FOST chapter); (ii) discovery and study of diffuse X-ray emission in HII<br />
regions excited by very massive stars. In turn, this has led, in the context of the Astromol team, to studies of<br />
X-ray irradiation effects (both in the vicinity of young stars and from diffuse emission) on the surrounding <strong>de</strong>nse<br />
molecular medium. SPITZER, a near to far Infrared telescope currently in orbit, is used (BL) to study regions<br />
of massive star formation and the proprieties of the energetic outflows emanating from young protostars. ISO<br />
(the ESA far Infrared telescope in orbit until 1999) data are still reduced and used to study regions of low mass<br />
star formation (CC, BL).<br />
Ground-based telescopes: Astromol members (BL, CC, AF, LW, CK) are heavy users of the IRAM, JCMT and<br />
CSO millimeter and submillimeter telescopes. They also regularly use radio telescopes like GBT (10 hours in<br />
2005) or VLA, though at a less extent. Table 2.3 summarizes the amount of 2002-2005 allocated time at IRAM,<br />
JCMT and CSO telescopes to proposals where members of Astromol are within the first three co-proposers. The<br />
Telescope 2002 2003 2004 2005<br />
IRAM-30m 300 300 363 180<br />
IRAM-PdBI - 1 5<br />
JCMT 128 132 95 330<br />
CSO - 50 90 100<br />
Table 2.3: Time allocated (in hours, except for IRAM-PdBI, where the number of nights are reported) to the<br />
different telescopes used by members of Astromol.<br />
45
Table shows not only the volume of the observational activity, but also the trend in the use of the telescopes. It<br />
is worth noting the positive gradient in the use of the CSO and JCMT submillimeter bands, and the net increase<br />
of the use of the IRAM interferometer PdB. Both trends shows how very naturally Astromol is preparing itself<br />
at the best exploitation of the two future big international projects: Herschel and ALMA.<br />
2.3 Development of astrophysical mo<strong>de</strong>ls<br />
Two classes of mo<strong>de</strong>ls have been <strong>de</strong>veloped within the Astromol team:<br />
i) Radiative transfer mo<strong>de</strong>ls (CC) that compute the line emission from the collapsing envelopes, for several<br />
molecules (H2O, CO : Ceccarelli et al. 1996, 2003; CH3OH : Maret et al. 2005; SO and SO2 : Wakelam<br />
et al. in prep; HDO : Parise et al. 2005). Astromol (CC, BL) also <strong>de</strong>veloped a simple LVG co<strong>de</strong> for the<br />
first level of analysis in more general conditions (like for example outflows). Some results of these mo<strong>de</strong>ls<br />
are ma<strong>de</strong> publicly available at the WEB site:<br />
http://www-laog.obs.ujf-grenoble.fr/∼ceccarel/mepew/mepew.html.<br />
ii) Chemical mo<strong>de</strong>ls of star forming regions (CC). We have <strong>de</strong>veloped co<strong>de</strong>s specialized in the Sulphur chem-<br />
istry (Wakelam et al. 2004, 2005), in the molecular <strong>de</strong>uteration due to grain surface (Parise et al. 2005),<br />
and <strong>de</strong>uterium chemistry of the ion H + 3 in protostellar disks (Ceccarelli & Dominik 2005).<br />
In addition, Astromol members (LW, AF, CC, BL, PV) have un<strong>de</strong>rtaken recently a systematic theoretical and<br />
observational survey of the cyanopolyyne family of rod-like molecules, of general formula HC2n+1N. It should<br />
serve as a prelu<strong>de</strong> to several new lines of observations and theories for larger molecules (notably organic complex<br />
molecules) in several types of astrophysical environments.<br />
2.4 Molecular physics: theories and co<strong>de</strong>s<br />
Several classes of new theoretical and algorithmic tools to solve molecular physics problems relevant to astrophysics<br />
are currently <strong>de</strong>veloped and used in the Astromol team. They can be regrouped in the following<br />
classes:<br />
i) A quantum chemistry co<strong>de</strong> that takes into account explicitely the correlation cusp between each electron<br />
pair. The fulfillment of this mathematical condition permits to approach the infinite basis set limit at the<br />
coupled cluster level of theory and to achieve an accuracy in the cm −1 range for the interaction of small<br />
non-reactive molecules.<br />
ii) A generalization of the so-called Transition State Theory for inelastic processes. This new method provi<strong>de</strong>s<br />
a geometrical view of the problem, and it promises to simplify the computation of the molecular collisional<br />
cross-sections.<br />
iii) A new strategy for computing inter-molecular potential surfaces which inclu<strong>de</strong>s the intra-molecular motion<br />
(i.e. the motion of the nuclei in each interacting molecule). The problem here is the sampling of the<br />
surface, which has several dimensions (≥ 4). For this, we implemented an optimized sampling, based on<br />
the high-accuracy vibrational wavefunctions.<br />
iv) A new strategy for computing inter-molecular potential surfaces of long rod-like molecules, like HC3N with<br />
He or H2. In these systems, the surface is highly anysotropic and, therefore, the fitting in the angular<br />
coordinates is particularly difficult, and this is known as “steric hindrance problem”.<br />
v) A quasi-classical scattering co<strong>de</strong>, based on a canonical Monte-Carlo strategy, to directly compute the<br />
collisional rates (with no need to integrate the cross-sections over the Boltzman velocity distribution).<br />
The computations briefly <strong>de</strong>scribed above are very CPU-time consuming and require a large amount of time of<br />
high-performance computers, like the IDRIS and CINES supercomputers. For this reason, Astromol members<br />
46
(PV) are also involved in several high performance computing initiatives, like the <strong>de</strong>velopment of computer grids<br />
projects (CiGri, a project fun<strong>de</strong>d by the <strong>Grenoble</strong> ACI GRID, with the involvement of the institutes INRIA<br />
and IMAG). In this context, it is worth mentioning the UJF project CIMENT (Calcul Intensif, Mo<strong>de</strong>lisation,<br />
Experimentation Numerique et Technologique) co-fun<strong>de</strong>d by the government and the region Rhone-Alpes, whose<br />
scope is to create and upgra<strong>de</strong> several computational platforms and associated centers of expertise.<br />
2.5 Publications<br />
In the last four years, the members of Astromol have published about 100 articles in international refereed<br />
Journals. It is worth noticing that the Astromol articles account for about 15% of the total publications<br />
reported in the last “Rapport d’activité <strong>de</strong> PCMI: Prospectives et Bilan 2001-2004”. In addition, the value of the<br />
Astromol work is testified by the several systematic invitation to present their works in national and international<br />
congresses. It is probably worth noticing the invitations for review talks at the four major Congresses of the<br />
field: the IAU Astrochemistry Symposium -held in Asilomar (CA) in Aug 2005, the Protostar and Planet<br />
VI Workshop -Kona (Hawaii) in Oct 2005, the Pacifichem Technical Workshop on Astrochemistry -Honolulu<br />
(Hawaii) in Dec. 2005, and the Nobel Symposium on “Astrochemistry” -Stockolm (Swe<strong>de</strong>n) in Jun 2006organized<br />
by the Nobel Foundation.<br />
2.6 Teaching and stu<strong>de</strong>nts formation<br />
Four members of Astromol have an intense teaching activity and important administrative charges at the<br />
University Joseph Fourier (UJF).<br />
• Administrative charges:<br />
– C.Kahane is the Director of the Departement Scientifique Universitaire (DSU), the structure responsible<br />
for the re-organization of the “L1L2 <strong>de</strong> la Licence <strong>de</strong> Sciences et Technologies”;<br />
– C.Kahane is member of CEVU and member of “la commission <strong>de</strong> finances <strong>de</strong> l’UJF”;<br />
– J-J. Benayoun is responsible of the first year of the Master <strong>de</strong> Physique.<br />
• Teaching: Members of Astromol teach at all levels from the first year to the Master <strong>de</strong>gree.<br />
• PhD Thesis :In the last four years three stu<strong>de</strong>nts (Sebastien Maret, Berengere Parise et Valentine Wakelam)<br />
have been co-directed by members of Astromol and are now Post-Docs at International Institutes.<br />
Two more stu<strong>de</strong>nts (Michael Wernli and Sandrine Bottinelli) have started their PhD thesis directed by<br />
members of Astromol.<br />
2.7 National and international collaborations<br />
Astromol is involved in several major and minor projects, in collaborations with groups from France and worldwi<strong>de</strong>.<br />
These projects are briefly <strong>de</strong>scribed in the following list:<br />
• WAGOS: Astromol is part of the network WAGOS (Working Astronomical Group on Star formation),<br />
between about two dozens of researchers in <strong>Grenoble</strong> (LAOG), Toulouse (CESR), Bor<strong>de</strong>aux (L3AB), and<br />
Paris (LERMA). WAGOS has been fun<strong>de</strong>d by the “Project National” PCMI since its creation in 2000.<br />
The goal of the network is the study of the solar type star formation, one of the goals of Astromol itself<br />
(§2.1). In<strong>de</strong>ed Astromol plays a major role in this network, with several Astromol members (CC, AF,<br />
BL, TM, PV, LW) belonging to it. The coordinator of this network is a member (CC) of Astromol. For<br />
the next “quadriennale”, 2007-2010, we have submitted a proposal for a PPF to coordinate and fund the<br />
activities of WAGOS.<br />
47
• Herschel-HIFI: Astromol is involved in the scientific preparation of the heterodyne instrument HIFI, on<br />
board the ESA satellite Herschel Space Observatory (HSO), which will be launched beginning 2008. One<br />
of the Astromol members (CC) is the coordinator of the team “Star Formation” for the use of the HIFI<br />
Guaranteed Time, and coordinator of the Herschel Key Program “Spectral Surveys of Star Forming<br />
Regions”.<br />
• FP6-THE MOLECULAR UNIVERSE is a network financed by the EC in the FP6 plan, in preparation<br />
of the Herschel mission. The goal of the network is to provi<strong>de</strong> the tools for the best interpretation<br />
of observations of molecules in the space. This means computing the molecular data relevant for the<br />
astrophysical observations, as well as the <strong>de</strong>velopment of astrophysical mo<strong>de</strong>ls for their interpretation.<br />
They are both among the goals of Astromol itself (§2.1), and, in<strong>de</strong>ed Astromol plays a major role in<br />
several milestones of the network, as well as in its management. In addition, being a training network, a<br />
major goal is the formation of young researchers. Astromol is also a major actor in this aspect, helping<br />
in the preparation of the 2005 Summer School “Molecular Astrophysics” and offering a post-doc position.<br />
• ALMA: Astromol is involved in the preparation of the ALMA project, contributing to the project “Action<br />
Specific pour ALMA” (ASA) with two of its members (CK and PV).<br />
• Projets Nationaux: PCMI and PNPS. Astromol regularly obtains funds from PCMI since its creation,<br />
and participate to its board (BL). It substantially contributes to the scientific results of PCMI, with about<br />
15% of refereed articles. Lately, Astromol has also obtained PNPS funds for the study of proto-planetary<br />
disks, in collaboration with FOST members (see §3.5).<br />
• CNRS/NSF project “Cyanopolyynes in the interstellar space”. Since 2004 Astromol (LW, CC, BL, AF,<br />
PV) received funds to collaborate with the University of California of Los Angeles (UCLA; M.Morris) in a<br />
project that aims to study the formation and evolution of cyanopolyynes in several regions of our Galaxy;<br />
from cold molecular clouds to star forming regions and regions close to the Galactic Center.<br />
• PAI vanGogh project “Proto-planetary disks”: since 2005 Astromol (CC and BL) has been fun<strong>de</strong>d to<br />
collaborate with the University of Amsterdam in a project which aims to study some key aspects of the<br />
physics and evolution of proto-planetary disks: the ionization in the disk midplane, the evolution of the<br />
dusty and gaseous components of the disk, and the effects of the disk irradiation from the central source.<br />
This project involves also members of the FOST team (see also §3.5).<br />
• JETSET : this is a EC FP6 network, <strong>de</strong>scribed in <strong>de</strong>tail in the FOST chapter.<br />
• CIMENT is UJF project “CIMENT” (Calcul Intensif, Modélisation, Expérimentation Numérique et Technologique),<br />
<strong>de</strong>tailed in subsection “High Performance Computing” (§3.4).<br />
In addition, Astromol members have collaborations with several colleagues world wi<strong>de</strong>: P.Caselli (Arcetri<br />
Obs., Italy), J.Cernicharo (Madrid, ES), Feigelson (Pen.State Un., USA), E.Herbst (Columbus, USA), D.Hollenbach<br />
(Nasa Ames, USA), J.Noga (Bratislava, SK), J.Tennyson (Un.Col.London, UK), X.Tielens (Groningen, NL),<br />
Moshe Elitzur (Univ. kentucky, USA) just to mention the most important collaborations.<br />
48
Chapter 3<br />
Results<br />
3.1 Overview<br />
In this chapter we will briefly <strong>de</strong>scribe the activity of Astromol, enlightening the major results achieved during<br />
the period 2002-2005. This chapter is structured into three sections. The first section <strong>de</strong>scribes the results<br />
relative to the “Star Formation” activity, while the second section reports the results relative to the “Molecular<br />
Physics” studies. A third section will <strong>de</strong>scribe in <strong>de</strong>tail the research about the “Proto-planetary Disks”, which<br />
is a “meeting point” of the Astromol and FOST teams. This is treated as a separate section to emphasize the<br />
synergy between the two LAOG teams on such an important and hot field of research.<br />
Before giving a brief <strong>de</strong>scription of the overall activities, we report here the three most important results<br />
achieved by the Astromol team in the last four years. They are:<br />
i) The study of the molecular <strong>de</strong>uteration in the regions of low mass star formation: Astromol, in collaboration<br />
with WAGOS, had and keeps having an important role in this field of research, with the discovery of<br />
doubly and triply <strong>de</strong>uterated molecules with D/H ratios enhanced by up to 13 or<strong>de</strong>rs of magnitu<strong>de</strong>s with<br />
respect to the D/H elemental abundance ratio (e.g. Parise et al. 2004). We are proud to say that our<br />
first results on the subject, starting from 1998 (Ceccarelli et al. A&A 338, L43), have given a new élan to<br />
this field, and triggered a flurry of new observations and new theories about the molecular <strong>de</strong>uteration in<br />
cold and <strong>de</strong>nse gas. It is important to emphasize that the new observational and theoretical framework of<br />
molecular <strong>de</strong>uteration has lead to recognize not only the role of the grain surface and gas phase chemistry<br />
during the pre-collapse phase, but also to i<strong>de</strong>ntify the only way we have to probe the innermost regions of<br />
the pre-stellar cores and the midplane of proto-planetary disks : the H2D + and HD + 2<br />
ground transitions<br />
in the submillimeter (Caselli et al. 2003; Ceccarelli et al. 2004). They not only give us the information<br />
about the dynamics in those regions, but also, and not least, the measure of the gas <strong>de</strong>gree of ionization,<br />
a key quantity in both classes of objects (Ceccarelli & Dominik 2005. Our leading role in these studies<br />
is testified by the several invitations to international congresses to review the subject (for a list of our<br />
articles on this subject see §3.2.2).<br />
ii) The chemical composition of the envelopes of the youngest low mass protostars, and the discovery of the<br />
hot corinos, warm and <strong>de</strong>nse regions where complex organic molecules are abundantly formed (Cazaux et<br />
al. 2003). Astromol, in collaboration with WAGOS, had and keeps having a leading role on this field,<br />
as testified by the several invitations to international congresses to give reviews on the subject. We were<br />
the first to predict the existence of warm and <strong>de</strong>nse regions around low mass protostars (Ceccarelli et al.<br />
2000, A&A 357, L9), and to prove it with several observations. The most important findings is that these<br />
regions have sizes comparable to those of our Solar System (few tens of AUs; Maret et al. 2004), and that<br />
complex organic molecules are formed there, against the first theoretical expectations. We were also the<br />
first to obtain the resolved images of the first discovered hot corino (around IRAS16293-2422: Bottinelli<br />
et al. 2004b) with the PdB interferometer in two complex organic molecules.<br />
iii) Consi<strong>de</strong>rable progress has been achieved in the accurate <strong>de</strong>termination of intermolecular interactions with<br />
the combination of explicitely correlated ab-initio approaches and multi-dimensional investigations. In<br />
49
particular, we calculated a 9D H2O-H2 potential energy surface of unprece<strong>de</strong>nted accuracy and complexity<br />
(Faure et al 2005a). The associated quenching rate for vibrationally excited water has been calculated<br />
using a classical Monte Carlo canonical approach which corrects by more than one or<strong>de</strong>r of magnitu<strong>de</strong><br />
the existing estimations (Faure et al 2005b). These results will lead to a thorough re-interpretation of<br />
vibrationally excited water emission spectra from space.<br />
iv) We have also reconsi<strong>de</strong>red the role of electrons in the collisional excitation of molecules in harsh environments<br />
(PDR’s, planetary nebulae, etc) in collab. with the group of J. Tennyson at UCL. Rotational<br />
transitions with ∆J > 1, which are neglected in pure dipolar approximations, were found to have rate<br />
constants similar or even larger than those with ∆J = 1. Results of astrophysical relevance have been<br />
obtained for H + 2 , CO+ , NO + , HCO + , H + 3 , H3O + , and asymmetric-top isotopologs of water H2O, HDO<br />
and D2O (Faure et al. 2004 and references therein).<br />
3.2 Star Formation<br />
3.2.1 Overview<br />
Astromol members carry out observational and theoretical studies of the star formation process. These cover<br />
low to high mass (§3.2.5) stars, and concern the very first stages represented by the Molecular Clouds and<br />
Pre-Collapse phases to the last phases before the so called Pre-Main-Sequence (PMS) phase, which is a target<br />
of the FOST team research. Specifically, Astromol studies focus on:<br />
• Molecular Clouds, as the nurseries of newly forming stars (§3.2.2, 3.2.6);<br />
• Pre-Stellar Cores, the con<strong>de</strong>nsations just before the collapse sets in ((§3.2.2);<br />
• Class 0 sources, believed to be the youngest known protostars (§3.2.2, 3.2.3, 3.2.6, 3.2.7);<br />
• Class I sources, believed to represent the transition between Class 0 sources and PMS objects (§3.2.2,<br />
3.2.3, 3.2.6, 3.2.7);<br />
• Proto-planetary disks (this part is <strong>de</strong>scribed in §3.5)<br />
• Molecular outflows, the result of the interaction of the material ejected during the Class 0 and Class I<br />
phases with the surrounding Molecular Clouds (§3.2.4).<br />
To study the formation of the stars and how this influences the surroundings, Astromol members use observational<br />
facilities which span the X-ray (§3.2.6) to radio frequency range. In addition, although molecular<br />
spectroscopy is the Astromol privileged tool to study star forming regions, also dust continuum emission and<br />
features (§3.2.7) have been used by the Astromol members. Consequently, a wi<strong>de</strong> range of mo<strong>de</strong>ls is <strong>de</strong>veloped<br />
to interpret such a wi<strong>de</strong> range of observations. The following sections give a brief summary of the Astromol<br />
research in the mentioned fields.<br />
3.2.2 The <strong>de</strong>uteration in the first phases of star formation<br />
Molecular <strong>de</strong>uteration was consi<strong>de</strong>red sort of a solved problem in Astrophysics, until the first <strong>de</strong>tections of<br />
multiply <strong>de</strong>uterated molecules in low mass star forming regions, which showed molecular D/H ratios enhanced<br />
by up to 8 or<strong>de</strong>rs of magnitu<strong>de</strong> with respect to the elemental D/H ratio (Ceccarelli et al. 1998 A&A 338, L43;<br />
2001 A&A 372, 998; 2002 A&A 381, L17; Loinard et al. 2000 A&A 359, 1169; 2001 ApJ 552, L173). The<br />
current mo<strong>de</strong>ls were unable to fully explain those observations (e.g. Roberts & Millar 2002, A&A 361, 388).<br />
Astromol observational work in the 2002-2005 period has helped to solve the problem, which now is much better<br />
mastered. Specifically, the following aspects were elucidated:<br />
• The extreme <strong>de</strong>uteration observed in low mass protostars sets on during the pre-collapse phase, when the<br />
matter is very <strong>de</strong>nse (≥ 10 6 cm −3 ) and cold (≤ 10 K). This is in the so called Pre-Stellar-Core phase. A<br />
key factor which makes the <strong>de</strong>uteration so extreme is the CO freeze-out onto the grain mantles (Bacmann<br />
50
et al. 2002, 2003). When CO disappears from the gas phase (because con<strong>de</strong>nsed onto the grain mantles),<br />
ratio is highly enhanced and can reach the unity (Caselli et al. 2003). Besi<strong>de</strong>s, even the<br />
the H2D + /H + 3<br />
multiple <strong>de</strong>uterated forms of H + 3 , namely HD+ 2 and D+ 3 , can become more abundant than H+ 3 (Roberts,<br />
Herbst & Millar 2003, ApJ 591, L41). Since the <strong>de</strong>uterated forms of H + 3 react with all molecules in the<br />
gas phase exchanging the D atom, they transmit the <strong>de</strong>uteration to molecules (e.g. Roberts, Herbst &<br />
Millar 2004, A&A 424, 905).<br />
• Molecules like H2CO, CH3OH and H2S, which are thought to form on the grain surfaces rather than in<br />
the gas phase, have been found to show up the largest multiple <strong>de</strong>uteration factors (Parise et al. 2002,<br />
2004a; Vastel et al. 2003). Very likely this is because they are formed by hydrogenation of CO (and S)<br />
during the last phases of the pre-collapse, when the CO <strong>de</strong>pletion is larger (this is a <strong>de</strong>finition!).<br />
• Water though does not follow the same route. In<strong>de</strong>ed, the gaseous HDO/H2O ratio is less than 3% in low<br />
mass protostars (Parise et al. 2005), whereas HDCO/H2CO and CH2DOH/CH3OH ratios are around<br />
30%. Even the solid HDO/H2O ratio is in<strong>de</strong>ed less than 3% (Parise et al. 2004b), which confirms the<br />
lower <strong>de</strong>uteration of water. One possible interpretation is that water forms on the grain surfaces at an<br />
higher temperature, because the H2O con<strong>de</strong>nsation occurs already at about 100 K. This would limit the<br />
H2D + /H + 3 ratio.<br />
• At the center of the Pre-Stellar Cores, all CO is now believed to almost completely freeze-out onto the<br />
grain mantles. Therefore, CO and all the other heavy-bearing molecules disappear from the gas phase,<br />
and the best tool to probe those regions is the H2D + emission (Caselli et al. 2003). The study of the<br />
profile of the H2D + ground state transition provi<strong>de</strong>s a valuable tool to probe the velocity field at the<br />
center of the con<strong>de</strong>nsation, and, consequently, whether and how the collapse sets in (van <strong>de</strong>r Tak, Caselli<br />
& Ceccarelli 2005).<br />
• Similarly to the centers of the Pre-Stellar Cores, the gas in the midplane of the proto-planetary disks<br />
surrounding solar type protostars can only be probed by the H2D + emission (Ceccarelli et al. 2004,<br />
Ceccarelli & Dominik 2005). This aspect will be discussed in more <strong>de</strong>tail in §3.5.<br />
3.2.3 The hot corinos of solar type protostars<br />
In the first phases of the star birth, the future star is embed<strong>de</strong>d in and totally obscured by the infalling material,<br />
which forms a thick envelope. The <strong>de</strong>nsity in the envelope ranges between 10 4 to 10 8 cm −3 , and the temperature<br />
ranges between 10 and about 200 K. The exact <strong>de</strong>nsity and temperature structure <strong>de</strong>pends on the dynamics of<br />
the collapse. It is therefore extreme important to study the <strong>de</strong>nsity and temperature profiles of these envelopes<br />
and how they evolve with time. Furthermore, giving the involved <strong>de</strong>nsities and temperatures, protostellar<br />
envelopes are privileged sites for a rich chemistry to occur. The chemical composition of these envelopes is<br />
not only interesting in itself. The matter in protostellar envelopes forms the proto-planetary disks, which will<br />
eventually form the planets and comets. During the comets bombarding phase, molecules formed during the<br />
protostellar collapse phase may be preserved ( for example frozen-out onto the dust grains) and brought to<br />
the formed planets. It is therefore of paramount importance to know the molecular complexity reached in the<br />
protostellar envelopes. In this context, Astromol members, in collaboration with WAGOS, have contributed to<br />
three major aspects:<br />
• The study of the physical structure. Astromol members published the very first articles reconstructing<br />
the <strong>de</strong>nsity and temperature profiles of protostellar envelopes ( Ceccarelli et al. 2000 A&A 355, 1129;<br />
2000 A&A 357, L9; 2001 A&A 372, 998; Maret et al. 2002, 2004, 2005). Based on these studies, the<br />
protostellar envelopes have approximatively the structure of free-infalling envelopes, as predicted by the<br />
insi<strong>de</strong>-out theory by Shu and colleagues. In addition, they possess warm and <strong>de</strong>nse regions close to the<br />
central object where the icy grain mantles sublimate, injecting into the gas phase the molecules formed<br />
and/or trapped into the mantles.<br />
• The study of the chemical composition. Chemically, the protostellar envelopes are formed by two components:<br />
i) an outer envelope (<strong>de</strong>fined by where the dust temperature is less than ∼ 100 K), whose chemical<br />
composition is similar to that in molecular clouds; ii) an inner envelope, where the chemistry is dominated<br />
by the material sublimated from the icy grain mantles. In this inner envelopes, large quantities of H2O,<br />
H2CO, CH3OH, SO and SO2 molecules are found (Maret et al. 2002, 2004, 2005; Wakelam et al. 2004a,<br />
2004b).<br />
51
• The hot corinos. More spectacular, abundant complex organic molecules in the inner envelopes have been<br />
discovered by Astromol (Ceccarelli et al. 2000, A&A 362, 1122; Cazaux et al. 2003; Bottinelli et al.<br />
2004b). Following these reports, a (short living) <strong>de</strong>bate about the nature of these hot corinos arose, which<br />
was settled by the first images of hot corinos. These images (obtained with PdB -Bottinelli et al. 2004band<br />
SMA -Kuan et al. 2004 ApJ 616, L27) show that in<strong>de</strong>ed complex molecules are formed in very small<br />
regions ( ∼ < 100 AU) close to the central object, as predicted by the previous Astromol studies (see Fig.<br />
3.1).<br />
The importance of the contribution of the Astromol studies in this field are testified by the invitation to give<br />
review talks in the major 2005 (just to mention the most recent ones) congresses of the field: the IAU 231<br />
Symposium on “Astrochemistry”, the Symposium “Protostars and Planets V”, and the Nobel Symposium 133<br />
“Cosmic Chemistry”<br />
Figure 3.1: The 1.3mm continuum (upper panel) image of the solar type protostar IRAS16293-2422, which is<br />
formed by a proto-binary system. The lower panel reports the same field as seen in one line of the methyl<br />
format (CH3OHCO). The North source is the brightest in the continuum, which implies that it is surroun<strong>de</strong>d<br />
by an envelope more massive than the South source. On the contrary, the South source shines in the molecular<br />
emission, whereas the North source is barely <strong>de</strong>tected. Very likely this corresponds to a different chemical<br />
composition of the two sources. The South source clearly possesses a “hot corino” about 300 AU in diameter,<br />
whereas the hot corino of the North source is smaller and/or less rich in molecules (from Bottinelli et al. 2004b).<br />
52
3.2.4 The outflows of protostars<br />
Astromol members have studied for several years the physics and chemistry of protostellar outflows, which are<br />
one of the most spectacular mass-loss phenomenon that takes place all along the protostellar phase. The current<br />
picture is that these outflows results from the acceleration and the sweeping up of ambient material by a faster,<br />
strongly collimated jet from the protostar. The main issues addressed by Astromol are the nature of the shock<br />
acceleration mechanism of the molecular gas, in particular the type of shock, either purely hydrodynamical (J-)<br />
or magnetohydrodynamical (C-), the relation the flow holds to the high-velocity atomic/ionized (Herbig-Haro)<br />
jet, and the impact of outflows on the parental cloud, both dynamically and chemically.<br />
Until now, most of the information on outflows has been <strong>de</strong>rived from observations probing the cold (20-<br />
50 K), post-shocked molecular material. However, the bulk of mass of the shocked molecular gas lies at much<br />
higher temperatures, in the range 100-2000 K, which can be probed by high-excitation molecular lines in the<br />
mm/submm domain. The data analysis relies strongly on comparison with shock diagnostics, for which we use<br />
state of the art mo<strong>de</strong>ls <strong>de</strong>veloped by Pineau <strong>de</strong>s Forets and S. Cabrit in LERMA (Paris).<br />
The confirmation that (MHD) C-shocks play a major role in the dynamics of outflows has been provi<strong>de</strong>d<br />
by ISO. The observation of pure H2 rotational lines with ISOCAM/CVF in the archetypal HH 1/2 system in<br />
Orion (Lefloch et al. 2003) has revealed large column <strong>de</strong>nsities of warm gas with excitation temperature Tex=<br />
500-1300 K, substantially cooler than the previously known component probed by the near-IR ro-vibrational<br />
H2 lines. Comparison with state of the art grid mo<strong>de</strong>ls (Cabrit et al. 2004) shows that the warm H2 column<br />
<strong>de</strong>nsity greatly exceeds that predicted for purely hydrodynamical (J-type) shocks, and allows to constrain the<br />
magnetic field. In the leading edge of the jet, where the geometry of the emission allows a simple mo<strong>de</strong>ling,<br />
the emission could be satisfyingly reproduced by MHD shock mo<strong>de</strong>ls with neutral-ion <strong>de</strong>coupling. This result<br />
appears quite general and is one of the most convincing evi<strong>de</strong>nces for C-shocks in outflows.<br />
The <strong>de</strong>termination of the physical conditions in the pre-shock and the shocked gas (<strong>de</strong>nsity, ortho-para ratio)<br />
requires the observations of additional molecular tracers. The molecules formed from the material released from<br />
dust grain mantles in the gas phase through shattering or sputtering in shocks are privileged tools for such study.<br />
SiO has long been recognized as a school case (Schilke et al. 1997 A&A 321, 293; Lefloch et al. 1998 ApJ 504,<br />
L109). The S-bearing species are also of particular interest as their chemistry is relatively fast (τ ∼ 10 4 yr). We<br />
have carried out several observational studies (Wakelam et al. 2004, 2005), which have required the <strong>de</strong>velopment<br />
of a time-<strong>de</strong>pen<strong>de</strong>nt chemical mo<strong>de</strong>l with up-to-date reaction rate coefficients. We could show that S-bearing<br />
molecular ratios cannot be easily used as chemical clocks, contrary to a suggestion ma<strong>de</strong> a few years ago by<br />
various authors, but it allows to constrain the <strong>de</strong>pleted form of sulphur onto grains (Wakelam et al. 2005).<br />
It has long been proposed that the X-ray/UV radiation produced in strong protostellar shocks could affect<br />
the chemical composition of gas and dust in the quiescent surroundings, and the region downstream of HH 2 (see<br />
above) was consi<strong>de</strong>red as an illustrative case of such processes. A <strong>de</strong>tailed study based on ISOCAM observations<br />
and the millimeter SO line emission showed however that the gas downstream of HH 2 was not as quiescent<br />
as claimed so far, and that the “anomalous” chemical gas composition was probably the result of previous<br />
protostellar ejections (Lefloch et al. 2005).<br />
3.2.5 The intermediate/high mass protostars<br />
A large number of observations indicate that HII regions play an important role in spreading star formation<br />
throughout the Galaxy. Most of the embed<strong>de</strong>d young stellar clusters in the solar neighborhood are adjacent<br />
to HII regions excited by more evolved stars, like Orion or Perseus OB2, to name but a few. It is estimated<br />
that 10%-30% of stars in mass in the Galaxy are formed un<strong>de</strong>r the influence of adjacent HII regions. Various<br />
scenarios of triggered star formation in the molecular layer surrounding the HII regions have been proposed<br />
(Elmegreen & Lada 1977 ApJ 214, 725; Whitworth et al. 1994 MNRAS 268, 291; Fukuda & Hanawa 2000 ApJ<br />
533, 911) but <strong>de</strong>tailed comparison with the observations, especially at early ages, is still missing. Two lines of<br />
investigation have been followed.<br />
i) In collaboration with J. Cernicharo (DAMIR, Madrid), we have started a systematic multi-wavelength<br />
study of the Trifid nebula (M20), from centimeter to near-IR wavelengths, which benefited the advent of ISO,<br />
allowing to study the properties of the Photon-Dominated Region at the interface between the nebula and<br />
the molecular cloud. A comprehensive picture of this young HII region (∼ 0.3 Myr) could be obtained, from<br />
53
the massive <strong>de</strong>eply embed<strong>de</strong>d protostellar cores and the bright rimmed globules <strong>de</strong>tected in the compressed<br />
surrounding cloud, to the “naked” cores and the protoplanetary disks exposed to the ionizing radiation in<br />
the nebula (Cernicharo et al. 1998; Lefloch & Cernicharo 2000, Lefloch et al. 2001, 2002). Recent Spitzer<br />
observations have unveiled the young stellar population of M20 and the protostellar cluster forming in the<br />
massive cores (see Fig. 3.2; Rho et al. 2005).<br />
ii) In collaboration avec L. Deharveng, A. Zavagno (Marseille), A. Whitworth (Cardiff), we have un<strong>de</strong>rtaken<br />
a multi-wavelength survey for evi<strong>de</strong>nces of induced star formation around young HII regions, to study the<br />
molecular emission of the parental cloud and compare the properties of the protostellar con<strong>de</strong>nsations and the<br />
young stellar clusters with the predictions of the scenarios of triggered star formation (see e.g. Deharveng et al.<br />
2004).<br />
Figure 3.2: Images of the Trifid Nebula in the visible (left panel) and in the Infrared (right panels). The IR<br />
images have been obtained by SPITZER Rho et al. 2005 and show the presence of many young stars invisible<br />
in the optical, because obscured by the thick dusty molecular cloud.<br />
3.2.6 The X-rays from young protostars<br />
• X-ray irradiation of circumstellar disks<br />
X-ray emission is ubiquitous among young stars (see Feigelson & Montmerle 1999, ARAA, 37, 363). In<br />
low-mass stars, the main X-ray emission mechanism is due to solar-type magnetic activity, which manifests<br />
itself mainly in the form of hour-long flares. The average X-ray luminosity (normalized to the stellar bolometric<br />
luminosity) is very high (LX/Lbol ∼ 10 −4 − 10 −3 ), i.e., three to four times higher than for the present-day Sun.<br />
In the case of young stars, the prime target for the X-rays is the circumstellar disk. The main effect is ionization<br />
(induced by the photoelectric effect): although the results <strong>de</strong>pend to some extent on the <strong>de</strong>nsity-radius relation,<br />
in most cases the disk is ionized throughout its extent, with representative values of the ionization fraction<br />
comparable to the average ISM (xe ≈ 10 −7 ) (Glassgold, Feigelson, & Montmerle 2000, Protostars & Planets IV,<br />
University of Arizona Press, p.429). The fact that the circumstellar disk is ionized (albeit weakly) is important<br />
because it provi<strong>de</strong>s a coupling between the disk material and magnetic fields, especially in the inner parts of<br />
the disk, close to the “accretion-ejection” engine. Note however that the <strong>de</strong>nsest parts of the disk, along the<br />
equatorial plane, may be too thick for X-rays to penetrate them, resulting in an embed<strong>de</strong>d “<strong>de</strong>ad zone”. It is<br />
possible that such a <strong>de</strong>ad zone, being neutral, be favorable to the formation of planets (see also the discussion<br />
in §3.5.<br />
Another effect is that of X-ray heating. Glassgold et al. (2005) have shown that this heating is efficient in the<br />
outer, tenuous layers of the disk, resulting in an exten<strong>de</strong>d (several tens of AU) warm photosphere (T ∼ 3, 000 K),<br />
explaining the observed CO overtone IR lines. As a result, the vertical temperature structure of circumstellar<br />
disks must be “inverted”, i.e., cold along the horizontal plane and warm at high altitu<strong>de</strong>s.<br />
54
Since X-rays mainly come from flares, as in the case of the Sun, one must also consi<strong>de</strong>r the effect of energetic<br />
particles hitting the disk. In particular, energetic protons and α nuclei generate nuclear spallation reactions on<br />
the gas, the resulting particles being subsequently trapped in macroscopic bodies like meteorites. This “internal<br />
irradation” scenario has successfully explained almost all the “extinct radioactivities” in solar system meteorites<br />
(Gounelle et al. 2001, ApJ, 548, 1051; Montmerle 2002, Feigelson et al. 2005).<br />
Taking a broa<strong>de</strong>r perspective, the irradiation phenomena that must have taken place during the very young<br />
stages of circumstellar disks around solar-type stars may set interesting boundary conditions for the origin of<br />
life (Montmerle 2005).<br />
• X-ray irradiation of molecular clouds<br />
After nearly three <strong>de</strong>ca<strong>de</strong>s of theoretical work and expectations, diffuse X-ray emission has been discovered<br />
massive star-forming regions (M17 : Townsley et al. 2004). This region is excited by about a dozen of O3<br />
stars (the most massive stars in the Galaxy). The diffuse X-ray emission was predicted as coming from a large<br />
hot bubble (T ∼ 10 7 K) of low-<strong>de</strong>nsity gas, inflated by the intense and fast stellar winds from these stars.<br />
With stellar mass-loss rates reaching ˙ M ∼ 10 −5 M⊙/yr and velocities vw ∼ 4, 000 km s −1 , bubbles several pc<br />
in size or more were expected. It took the sharp, subarcsec resolution of Chandra to distinguish truly diffuse<br />
X-ray emission from the unresolved X-ray emission of the thousands of low-mass stars present in such massive<br />
star-forming regions (Fig. 3.3).<br />
Figure 3.3: ISO pointings of M17, from the O star cluster into the molecular cloud, superimposed on the<br />
Chandra image. Square: ISOCAM field of view; Sn: SWS pointings; Ln: LWS pointings (dashed ellipse: fields<br />
in the direction of the molecular cloud). Thin, closely spaced isophotes: 330 MHz emission; loose isophotes:<br />
IRAS 100 µm emission.<br />
With an intense diffuse X-ray flux, spread over a large volume, it was important to search for large-scale Xray<br />
irradiation effects on the parent giant molecular cloud of M17. Several possible tracers, observed at different<br />
wavelengths, from the radio cm range to the mid-IR range (ISO spectroscopy), were examined from archival<br />
data (Montmerle & Vuong 2005). The results were however inconclusive (like exten<strong>de</strong>d excess C + emission),<br />
because of the presence, simultaneous with X-rays, of UV photons from the massive stars, able to travel to large<br />
distances in the tenuous, external layers of the molecular cloud. New, targeted observations in the mm range,<br />
are planned to probe the <strong>de</strong>nse parts of the molecular cloud, which only X-rays can penetrate.<br />
• X-ray absorption and metallicity of molecular clouds<br />
While X-rays are emitted by the young stars born in a molecular cloud, they are absorbed by the surrounding<br />
material, as explained above. Then one can take advantage of this absorption to map the column <strong>de</strong>nsity NH,X<br />
towards each star, by fitting the observed X-ray spectrum. X-rays are absorbed by heavy atoms, whatever the<br />
material (gas or grains) in which they are located. 1-10 keV X-rays can penetrate up to the equivalent of several<br />
55
tens of visual magnitu<strong>de</strong>s, hence probe <strong>de</strong>eply into the <strong>de</strong>nsest regions of molecular clouds. When correlated<br />
with the IR extinction in front of the same stars, which <strong>de</strong>pends essentially on the dust grain size distribution,<br />
one has in principle (with sufficient IR data) a powerful tool to measure the metallicity of molecular clouds.<br />
This was done successfully by Vuong et al. (2003) for the nearby ρ Oph cloud (up to AV ∼ 50), resulting<br />
in a solar cloud metallicity (Z ∼ Z⊙). Other clouds were also studied, but the available data do not probe<br />
sufficiently <strong>de</strong>nse regions to establish a good NH,X vs. AV correlation.<br />
3.2.7 Dust around protostars<br />
The continuum emission (spectral and spatial distributions) from the dust in the protostellar envelopes gives<br />
important information on the structure of the envelope. The study of the dust continuum is in fact a technique<br />
used by several groups in the world. It is complementary to that exposed in §3.2.3, which uses the rotational<br />
transitions of molecules. Astromol has used both techniques wherever the opportunity presented (Maret et<br />
al. 2004). However, Astromol research on the dust continuum has been more original in the analysis of the<br />
dust features in the Far Infrared, and specifically in the range (45-200 µm) observed by the Long Wavelength<br />
Spectrometer (LWS) on board ISO. This range of wavelengths was thought to not contain any interesting<br />
dust feature. However, Astromol has revealed that an important feature is observed between 90 and 100 µm<br />
(Ceccarelli et al. 2002b). A systematic study of the LWS spectra of low to intermediate protostars has found<br />
that more than 50% of the protostars show up this feature (Chiavassa et al. 2005). The nature of the carrier of<br />
the observed feature is not totally sure. At present, the most reasonable hypothesis is that calcite is responsible<br />
for it. In support of this interpretation, very recently calcite has been revealed in the comet Temple 1 (Deep<br />
Impact mission; Lisse et al. 2005, IAU Circular 8571). This is an important observation, because it shows a<br />
clear link between the comets and the proto-stellar phase. Furthermore, and mostly important, the presence of<br />
calcite in protostars and comets rises the question of its formation. On Earth and in the Solar System objects<br />
(meteorites), calcite is formed by aqueous alteration. However, both in protostars and comets, evi<strong>de</strong>ntly, no<br />
liquid water is present. We have proposed that the interaction of the X-rays emitted from the central object<br />
(§3.2.6) with the dusty envelope, could be at the origin of the calcite formation (Ceccarelli et al. 2002b). The<br />
interest in this discover is that, if the calcite interpretation is confirmed, this may have some far reaching<br />
consequences because the same mechanism forming calcite may be also form pre-biotic molecules.<br />
3.3 Molecular Physics<br />
3.3.1 Overview<br />
The near-future large scale observatories HERSCHEL and ALMA will open up the Universe to high spatial and<br />
spectral resolution studies of molecules. These new missions will make a major breakthrough in our knowledge of<br />
the key astrochemical processes involved in the origin and evolution of planets, stars, and galaxies. HERSCHEL<br />
and ALMA will lead to a multitu<strong>de</strong> of molecular line data in a great variety of astrophysical environments.<br />
I<strong>de</strong>ntification, analysis and interpretation of this data in terms of the physical and chemical characteristics of<br />
the astronomical sources will require a concerted effort by physicists, chemists and astronomers in the areas of<br />
molecular spectroscopy, collisional excitation processes, chemical reactions, and astronomical mo<strong>de</strong>ling.<br />
In this ambitious context, our objective since 2002 is to focus our theoretical activity on the calculation<br />
and renewal of potential energy surfaces (PES) and collisional data for astrophysics. Several recent studies<br />
have shown that inaccuracies in the PES are in<strong>de</strong>ed the largest source of error in collisional rate calculations.<br />
Furthermore, the standard quantum close-coupling method used to compute these rates is computationally<br />
efficient at low temperatures only. The <strong>de</strong>velopment of reliable approximate quantum treatments or methods<br />
based on classical mechanics are thus highly <strong>de</strong>sirable. The specific objectives of our theoretical work are<br />
therefore:<br />
• Calculations of PES at the highest level of accuracy by employing state-of-the-art ab initio methods.<br />
• Calculations of collisional rate constants by employing both full dimensional quantum calculations and<br />
practical quantum/classical approximations.<br />
56
• Monitoring of the error propagation from the PES to the collisional rates, and subsequent monitoring of<br />
the collisional approximations, with first results for inelastic rotational rates involving CO, HC3N, (also<br />
H2O and NH3 in collab. with M.L. Dubernet and E. Roueff), and for H2O quenching.Corresponding tools<br />
will be inclu<strong>de</strong>d in the BASECOL database.<br />
Furthermore, the <strong>de</strong>pen<strong>de</strong>nce of astronomical mo<strong>de</strong>ling to the accuracy of collisional rates is also a very<br />
challenging issue which our group has started to address.<br />
3.3.2 Potential energy surfaces<br />
Within the Born-Oppenheimer approximation, inelastic cross sections and rate constants are obtained by solving<br />
for the motion of the nuclei on an “electronic” PES, which is in<strong>de</strong>pen<strong>de</strong>nt of the masses of the nuclei. Recent<br />
studies have <strong>de</strong>monstrated that computational techniques employing advanced treatments for both electronic<br />
and nuclear motion problems have the ability to rival the accuracy of experimental data. These studies all<br />
employed convergent hierarchies of basis sets and correlation methods to solve the electronic structure problem.<br />
The CCSD(T)-R12 method<br />
In contrast to conventional calculations, correlated methods that inclu<strong>de</strong> explicitly the inter-electronic coordinates<br />
into the wave function can <strong>de</strong>scribe properly the electron-electron correlation cusp and offer a direct way<br />
of reaching the basis set limit values within a single calculation, i.e. without extrapolation. Among various<br />
explicitly correlated methods, the R12 coupled cluster theory with singles, doubles and perturbative triples<br />
(CCSD(T)-R12) (Noga & Kutzelnigg 1994 J. Chem. Phys., 101, 7738) is computationally practical and proved<br />
highly accurate (Ramajäki et al. 2004 Mol. Phys, 102 2297), in particular using a<strong>de</strong>quate R12-suited basis<br />
sets (Kedˇzuch et al. 2005 Mol. Phys., 103, 999). Generalizing the i<strong>de</strong>a of Kutzelnigg (Kutzelnigg 1985 Theor.<br />
Chim. Acta, 68, 445), in CCSD(T)-R12 one takes care of the correlation cusp by inclusion of linear terms in<br />
the inter-electronic coordinates into the exponential wave function expansion.<br />
Our corresponding production co<strong>de</strong> DIRCCR12 1 implements an original trick to accelerate the calculations<br />
of CCSD triples and is efficiently parallelized up to 6-8 processors. It provi<strong>de</strong>s auto-adaptative algorithms to<br />
handle load imbalance, heterogeneous processors and distributed scratch disks on clusters. It achieves a typical<br />
parallel performance over 500 Mflops per processor on the IBM Power4 Regatta supercomputer at IDRIS with<br />
minimal I/O bottlenecks. This co<strong>de</strong> is routinely used either for conventional CCSD(T) calculations or for<br />
explicitely correlated CCSD(T)-R12 using our specifically <strong>de</strong>veloped R12-suited basis sets for H to Ne.<br />
H2O – H2<br />
We have constructed a full nine-dimensional interaction potential for H2O – H2 calibrated using high-accuracy,<br />
explicitly correlated wave functions. All <strong>de</strong>grees of freedom are inclu<strong>de</strong>d using a systematic procedure transferable<br />
to other small molecules astrophysically or atmospherically relevant. CCSD(T)-R12 5D calibration<br />
calculations were run on the IDRIS and CINES national computers, while the Monte Carlo sampling of the<br />
9D hypersurface was the first dimensioning application of the <strong>Grenoble</strong> computer grid (CiGri), <strong>de</strong>veloped with<br />
support from the ACI Grid. The resulting 9D hypersurface contains in particular all relevant information to<br />
<strong>de</strong>scribe the interaction of H2 with all H2O isotopomers in zero point or excited bending states.<br />
As a first application, we estimated rate constants for the vibrational relaxation of the ν2 bending mo<strong>de</strong> of<br />
H2 O obtained from quasiclassical trajectory calculations in the temperature range of 500 – 4000 K. Our hightemperature<br />
(T > 1500 K) results are found compatible with the single experimental value at 295 K. Our<br />
rates are also significantly larger than those currently used in the astrophysical literature and will lead to a<br />
thorough reinterpretation of vibrationally excited water emission spectra from space (see Faure et al JCP 2005<br />
122, 221102).<br />
In a second paper (Faure et al, JCP 2005 123 104309) we emphasized the role of rotation in the vibrational<br />
relaxation of water. As a further conclusion of this quasiclassical analysis, we also predict that the popular<br />
1 see the repository http://www-laog.obs.ujf-grenoble.fr/∼valiron/ccr12/in<strong>de</strong>x.html for <strong>de</strong>tails on the co<strong>de</strong> and for related bib-<br />
liography<br />
57
quantum VCC-IOS approximation may fail to properly <strong>de</strong>scribe the H2 O quenching. This stresses the need<br />
to <strong>de</strong>velop more advanced approximation schemes to <strong>de</strong>scribe the ro-vibrational collisional processes involving<br />
molecules with large ∆J splittings such as water, ammonia, etc...<br />
HC3N – H2<br />
The “steric hindrance” problem solved, first quantum inelastic rates obtained.<br />
Two new PES have been calculated at a CCSD(T) level for the HC3N–He and HC3N–H2 systems by P. Valiron.<br />
The new HC3N–He agrees pretty well with the PES obtained by Akin-Ojo et al 2003. Pionnering CCSD(T)-R12<br />
calculations with 920 basis set orbitals and 10 occupied (with frozen core) permitted to assess the accuracy of<br />
this PES. Steric hindrance problems involving the HC3N rod limit the convergence of the angular expansion<br />
of the PES, as anticipated by Green & Chapman (1978 ApJS 37, 169). However for the low energy regime<br />
M. Wernli showned it is feasible to regularize the PES by smoothing out the repulsive walls and to achieve a<br />
perfectly converged angular expansion.<br />
Corresponding close-coupling calculations led to surprising results due to the rod-like features of the PES. Firstly<br />
quantum interferences strongly <strong>de</strong>favour odd ∆j transitions and favour even ∆j ones. This propensity rule is<br />
likely to favour the J=1 population for H2 <strong>de</strong>nsities in the 10 3 –10 4 cm −3 range. Secondly, <strong>de</strong>spite the very large<br />
HC3N dipole moment, the para-H2 and ortho-H2 rates are nearly i<strong>de</strong>ntical. While the even ∆j propensity rule<br />
could not be found in the quasiclassical calculations by Green & Chapman (1978 ApJS 37, 169), the new rates<br />
remain within the same or<strong>de</strong>r of magnitu<strong>de</strong> <strong>de</strong>spite the very cru<strong>de</strong> an electron gas mo<strong>de</strong>l PES. This is not too<br />
surprising as the rod-like features of the PES dominate the scattering.<br />
3.3.3 Energy transfer processes<br />
Energy exchange processes between molecules, atoms and particles are responsible for thermal balance and line<br />
formation in a great variety of astronomical environments. Molecular line emissions are generally produced in<br />
low-temperature (T < 1000 K) and low-<strong>de</strong>nsity (n < 10 10 cm 3 s −1 ) conditions far from thermodynamic equilibrium<br />
and through a complex competition between radiative and collisional processes. A <strong>de</strong>tailed knowledge of<br />
rate constants for all microscopic processes that drive the populations of the emitting levels is thus necessary<br />
to interpret the observed spectra. Despite some recent progress in laboratory measurements of state-to-state<br />
collision rates, astrophysical mo<strong>de</strong>ls still rely heavily on theoretical predictions owing to the vast network of<br />
relevant states which span a wi<strong>de</strong> range of excitation energies. During the past four years, our group have ma<strong>de</strong><br />
significant advances in the un<strong>de</strong>rstanding of molecule-molecule and electron-molecule collisions.<br />
Molecule-molecule collisions<br />
In standard molecular environments such as <strong>de</strong>nse interstellar clouds or star-forming regions (T < 300 K,<br />
n > 10 4 cm 3 s −1 ), hydrogen molecules H2 are the dominant exciting species. We have recently revisited the<br />
collisional excitation of three astronomically very important molecules: CO, H2O and HC3N in collisions with<br />
H2. As <strong>de</strong>scribed previously, the H2O−H2 and HC3N−H2 PES have been computed by our group using high<br />
accuracy ab initio methods. For CO-H2, we employed a very recent PES obtained by Jankowski and Szalewicz<br />
(2005). The accuracy of these three PES is similar and lies within a few cm −1 in the relevant regions of the<br />
PES. Such a precision is necessary at low temperatures (T < 50 K) to guarantee that inaccuracies in the PES<br />
represent only a small fraction of collision energies. Our main results for the above mentioned systems are<br />
summarized below:<br />
• Rotational excitation of CO by para- and ortho-H2<br />
Quantum close-coupling calculations were performed for rotational levels of CO up to 5 and temperatures<br />
in the range 5−70 K (Wernli et al 2005). Our results were compared with those obtained by Flower<br />
(2001) on a previous, less accurate, PES. The new rigid-rotor CO−H2 PES of Jankowski and Szalewicz<br />
(2005) was thus shown to strongly affect the resonance structure of the rotational cross sections at very<br />
low collision energies (E < 60 cm −1 ). As a result, the calculated rates at 10 K were found to differ by up<br />
to 50% with those obtained by Flower (2001). Conversely, at temperatures larger than about 70 K, the<br />
effect of the new PES was found to be only minor.<br />
58
Rate coefficient (cm 3 s -1 )<br />
1e-10<br />
1e-11<br />
1e-12<br />
−<br />
−<br />
1e-13<br />
0 1000 2000 3000 4000<br />
Temperature (K)<br />
Figure 3.4: Rate constant (in cm 3 s −1 ) as a function of temperature for the vibrational relaxation of H2O(v2 =<br />
1 → 0) by H2. QCT results are plotted as filled circles for T ≥ 1500 K (with error bars corresponding to 2 Monte-<br />
Carlo standard <strong>de</strong>viations) and as arrows (lower limits) for T < 1500 K. The dotted curve <strong>de</strong>notes empirical<br />
rates reported by (González-Alfonso et al. 2002 A&A, 386, 1074). The empty circle gives the experimental<br />
value of (Zittel & Masturzo 1991 J. Chem. Phys., 95, 8005) at 295 K. The solid line corresponds to a standard<br />
interpolation of the high temperature (T ≥ 1500 K) QCT results. Taken from Faure et al. (2005).<br />
• Vibrational relaxation of H2O(v2 = 1) by H2<br />
Classical calculations were carried out using our nine-dimensional H2O−H2 PES where only the bending<br />
mo<strong>de</strong> of water (first excited state at 1595 cm −1 above the ground state) was consi<strong>de</strong>red, i.e. all stretching<br />
mo<strong>de</strong>s were neglected. The quasi-classical trajectory (QCT) method was employed as an alternative to<br />
computationally impractical full close-coupling calculations. Our results, as presented in Fig. 3.4, have<br />
shown that the rate constant for vibrational relaxation is one to two or<strong>de</strong>rs of magnitu<strong>de</strong> greater than the<br />
empirical prediction used by astrophysicists. Our high-temperature results (T > 1500 K) were also found<br />
compatible with the single experimental point at 295 K. Moreover, we observed a significant rotational<br />
enhancement of the vibrational rates, suggesting that standard quantum approximations (e.g. VCC-IOS)<br />
might fail for molecule-molecule collision pairs with large rotational constants (Faure et al. 20005b).<br />
• Rotational excitation of HC3N by para- and ortho-H2<br />
Quantum close-coupling and classical calculations have been carried out at low temperatures (T < 50 K).<br />
Our major result, as illustrated in Fig. 3.5, is the presence of strong quantum interferences in the rotational<br />
rates. These interferences, which simply reflect the strong even anisotropy of the PES, are obviously absent<br />
in our classical results and those of Green & Chapman for HC3N−He (1978). The ∆J = 2 propensity<br />
rule was also shown to strengthen the inversion of the J = 1 rotational level of HC3N for H2 <strong>de</strong>nsities in<br />
the range 10 3 -10 5 cm −3 , thus giving new insights to the HC3N astronomical masers. Another important<br />
result is the complete absence of a para/ortho-H2 selectivity. This last result again reflects the particular,<br />
non-multipolar, anisotropy of the PES.<br />
• Methodological <strong>de</strong>velopments<br />
The previous results have required original <strong>de</strong>velopments in the framework of quasi/semi-classical and<br />
transition-state theories. In line with theories proposed a few years ago by Wiggins, Wiesenfeld and<br />
colleagues (Wiesenfeld 2004; Wiesenfeld 2005), we have thus exten<strong>de</strong>d and generalized the concept of<br />
transition states, wi<strong>de</strong>ly used in the un<strong>de</strong>rstanding of chemical reactivity, to rotationally inelastic collisions<br />
(Wiesenfeld, Faure & Johann 2003). We have also reconsi<strong>de</strong>red the semi-classical quantization of the rigid<br />
asymmetric rotor (such as H2O) and we have shown that standard classical trajectories cannot be employed<br />
to compute state-to-state cross sections in this case, owing to ambiguities in the assignment of the semiclassical<br />
action to a particular quantum states (Faure & Wiesenfeld 2004). As a result, collisions involving<br />
asymmetric top species does require a quantum treatment of rotation.<br />
59
Rate constant (cm 3 s -1 )<br />
1e-09<br />
1e-10<br />
1e-11<br />
1e-12<br />
1e-13<br />
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16<br />
Final J of HC N 3<br />
Figure 3.5: Rate constant (in cm 3 s −1 ) at 40 K for the rotational excitation of HC3N(J = 0) by para-H2 as<br />
a function of the final J. Our QCT results are plotted as grey open circles (with error bars corresponding to<br />
2 Monte-Carlo standard <strong>de</strong>viations). The black solid curve <strong>de</strong>notes quantum close-coupling calculations. The<br />
black dashed curve gives the classical results of Green & Chapman (1978 ApJS 37, 169) for He. Taken from<br />
Wernli et al. (2005).<br />
Electron-molecule collisions<br />
The fractional ionization or electron fraction ne is typically of the or<strong>de</strong>r of 10 −6 −10 −3 in photon-dominated<br />
regions or cometary comae and much smaller in <strong>de</strong>nse dark clouds. Electrons may however become efficient<br />
exciting species owing to their strong electrostatic interactions with molecules. In<strong>de</strong>ed, rate constants for<br />
electron-impact excitation of molecules are typically five or<strong>de</strong>rs of magnitu<strong>de</strong> greater than the corresponding<br />
ones for excitation by the dominant neutral species (H and H2). Electrons are thus the dominant collision<br />
partners as soon as ne > 10 −5 .<br />
In collaboration with the group of University College London hea<strong>de</strong>d by Jonathan Tennyson, we have recently<br />
reconsi<strong>de</strong>red the role of electrons in the excitation of molecules by employing the UK molecular R-matrix<br />
approach. Briefly, the R-matrix theory is based on a high accuracy ab initio <strong>de</strong>scription, insi<strong>de</strong> a sphere, of the<br />
electron-molecule interaction (see Gorfinkiel et al. (2005) and references therein). We have shown that simple<br />
long-range approximations, wi<strong>de</strong>ly used in the astrophysical literature, are not reliable for computing rotational<br />
or vibrational rates. In particular, rotational transitions with ∆J > 1, which are neglected in pure dipolar<br />
approximations, were found to have rate constants similar or even larger than those with ∆J = 1. As electron<br />
temperatures up to several thousands of Kelvin are nee<strong>de</strong>d, the adiabatic-nuclei-rotation approximation was<br />
employed in our calculations (Faure & Tennyson 2002). We have consi<strong>de</strong>red recently the following astronomical<br />
important species: the linear molecular ions H + 2 , CO+ , NO + and HCO + (Faure & Tennyson 2001 MNRAS<br />
325, 443); the symmetric-top molecular ions H + 3 and H3O + (Faure & Tennyson 2003); and the asymmetrictop<br />
isotopologs of water H2O, HDO and D2O (Faure et al. 2004a). Collisions of electrons with H2O are<br />
particularly interesting because these have been studied extensively experimentally. Figure 3.6 compares our<br />
results at 6 eV with the rotational excitation measurements of (Jung et al. 1982 J. Phys. B, 15 3535) and the<br />
elastic measurements of (Cho et al. 2004 J. Phys. B, 37 4639). We can notice the very good agreement with<br />
the elastic measurements of Cho et al. (2004) over the whole measured angular range. The agreement with<br />
the data of Jung et al. (1982) is also quite satisfactory (within 50%) in view of the experimental uncertainties.<br />
A good agreement between our calculations and the very low energy storage-ring measurements of Field and<br />
co-workers (in preparation) was also observed very recently, suggesting again that R-matrix calculations give<br />
an accuracy rivalling, and sometimes exceeding measurements (Faure et al. 20004b).<br />
60
Differential Cross Section (Å 2 sr -1 )<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
0 20 40 60 80 100 120 140 160 180<br />
Scattering Angle (<strong>de</strong>g)<br />
Figure 3.6: Computed and measured DCS of water at 6 eV. The present elastic (rotationally summed) DCS<br />
is given by the thick solid line. Other lines <strong>de</strong>note partial state-to-state DCS (dashed line: 0 → 1; solid line:<br />
0 → 0). The filled squares correspond to the experimental elastic DCS of (Cho et al. 2004 J. Phys. B, 37<br />
4639). The open circles and diamonds correspond respectively to the experimental pure elastic (∆j = 0) and<br />
rotationally inelastic (∆j = ±1) DCS of (Jung et al. 1982 J. Phys. B, 15 3535); the sum of both contributions<br />
is given by the stars. Taken from Gorfinkiel et al. (2005 Eur. Phys. J. D, 35, 231).<br />
3.4 High Performance Computing<br />
The Astromol team has been involved in several high performance computing initiatives to achieve its objectives.<br />
The most <strong>de</strong>manding issue was the construction of multi-dimensional ab-initio potential energy surfaces and their<br />
calibration to cm −1 accuracy using our explicitely correlated coupled cluster approach. The inelastic scattering<br />
calculations proved also very <strong>de</strong>manding, both at the classical level (to investigate the H2O quenching) and at<br />
the close coupling level (CO colliding with H2 and HC3N colliding with He and H2). In the future, exploration<br />
of multi-parametric mo<strong>de</strong>ls of astrophysical sources may also prove very <strong>de</strong>manding, as was already explored<br />
by S. Maret.<br />
In or<strong>de</strong>r to achieve our goals at optimal cost, we combined a hierarchy of approaches and machines.<br />
• Our <strong>de</strong>velopment benefited of a few <strong>de</strong>dicated PCs acquired with support of PCMI and CNES, and<br />
complemented at the end of 2004 by a 64-bit opteron biprocessor with 8 GB memory which was <strong>de</strong>voted<br />
to explicitely correlated investigations. This latter machine was also used as a testbed for the preparation<br />
of the invitation to ten<strong>de</strong>r for the upgra<strong>de</strong> of the computing center of the Observatory (see below).<br />
• Large ab-initio production calculations, either conventional or explicitely correlated, were run on the<br />
national supercomputers. We submitted a huge <strong>de</strong>mand in 2005 to boost the calculations of all the<br />
potential energy surfaces related to the “Molecular Universe” FP6 project. We obtained 60000 hours on<br />
the IDRIS and the CEA supercomputers and 100000 hours on the CINES.<br />
• Multi-dimensional potential energy surfaces were sampled by a multi-parametric Monte Carlo procedure.<br />
The 9-D surface for H2O-H2 required 375000 in<strong>de</strong>pen<strong>de</strong>nt geometries, each combining a counterpoise of<br />
3 ab-initio calculations resulting into over a million of short ab-initio runs. This computational challenge<br />
triggered a pluri-disciplinary <strong>de</strong>velopment of the <strong>Grenoble</strong> computer grid “CiGri” with the support of<br />
a 3-year CDD fun<strong>de</strong>d by the ACI GRID and a strong involvment of the STIC community (INRIA and<br />
IMAG). A CiGrid protopype permitted to gather about 200000 cpu hours on idle PCs and to achieve the<br />
9-D surface for H2O-H2 within two months. Presently CiGri matured to a convivial middleware, and has<br />
been used for classical scattering calculations in our team and by other projects (including optimisation<br />
studies for the MARSIS sub-surface radar observations on Mars Express).<br />
61
• One of us (PV) is strongly involved in the UJF project “CIMENT” (Calcul Intensif, Modélisation,<br />
Expérimentation Numérique et Technologique) fun<strong>de</strong>d by the state and the region, which permitted the<br />
creation and upgra<strong>de</strong> of several computational platforms and associated expertise centers. The originality<br />
of CIMENT is to fe<strong>de</strong>rate user communities with computer science ones, and was a “cement” for the emergence<br />
of the <strong>Grenoble</strong> computer grid. CIMENT has fun<strong>de</strong>d in 2005 the upgra<strong>de</strong> of the computer resource<br />
center of the Observatory which is shared between astrophysicists, planetologists, geophysicists, etc. The<br />
new machine is a high performance cluster (30 quadriprocessors, 256 GB of core memory, 4 TB disk, over<br />
0.6 Tflop of peak performance) and will boost all high performance initiatives in the Observatory.<br />
• In the future, we plan to <strong>de</strong>velop tools for harnessing computer grids into the Virtual Observatory, in<br />
particular to trigger multi-parametric mo<strong>de</strong>lisations of a set of objets selected by a VO request. Such a<br />
coupling needs a proper specification and scheduling of the related data flow. A pluri-disciplinary project<br />
involving in particular the Observatory and the laboratory ID (Informatique et Distribution) has been<br />
submitted to the ANR in september 2005. Other <strong>de</strong>velopments may be carried on within the GRID’5000<br />
national initiative in collaboration also with colleagues from ID.<br />
3.5 Proto-planetary Disks: where Astromol meets FOST<br />
The study of the proto-planetary disks <strong>de</strong>serves an ad hoc section, because of both of its scientific interest<br />
and the fact that it is also an important field of research for the FOST team. While the FOST Team focuses<br />
mostly on the dust component of the disks, the Astromol team focus is rather the gaseous component. The<br />
two approaches are evi<strong>de</strong>ntly strictly linked and complementary, and, for this reason, Astromol and FOST<br />
have started a tight collaboration on this theme. This is testified by the beginning of publications in common<br />
(Duchene et al. 2005), the writing of new observing proposals at IRAM (30m and PdB) and Keck telescopes,<br />
the project PAI vanGogh project “Proto-planetary disks” (§2.7) which involves both members of Astromol (CC<br />
and BL) and FOST (F.Menard) and their stu<strong>de</strong>nts.<br />
A notable example of the importance of the dust-gas link in proto-planetary disks is represented by the<br />
interplay between the small dust grains and the gas. In<strong>de</strong>ed, the gas in the disk governs the dynamics of small<br />
dust grains. Dust grains try to settle towards the midplane, and the gas is critical in slowing down this motion<br />
and countering it by turbulent mixing. Without gas, the dust would collapse (basically within a single orbital<br />
timescale) entirely to the midplane until large (Moon-sized) bodies are able to stirr the disk gravitationally.<br />
With gas present, but without efficient turbulent mixing, the dust would settle within about 10 4 –10 6 years down<br />
to about one gas-pressure scale height (Dullemond and Dominik, 2004 A&A 421, 1075). However, observations<br />
show that disks as old as 10 Myrs contain significant amounts of dust at large heights above the midplane,<br />
<strong>de</strong>monstrating that the interaction between the grains and the gas is not only taking place, but it is in<strong>de</strong>ed a<br />
crucial aspect of the disk evolution.<br />
The reciprocal is also true: the presence of dust grains has a dramatic effect on the gas structure, thermal<br />
balance, chemistry and dynamics (where all these aspects are strictly inter-related). In the disk upper layers<br />
exposed to the protostar radiation, the radiation is almost totally absorbed by the grains, and the energy<br />
transmitted indirectly to the gas by the collisions with the grains and/or by electrons emitted from grains by<br />
the photoelectric effect (Bakes and Tielens, 1994 ApJ 427, 822). The formation of molecules, which can very<br />
effectively cool the gas, occurs only in the regions where the photoionizing photons are absorbed by the dust.<br />
Further down, in the disk midplane, the molecules freeze out onto the grains and disappear from the gas phase,<br />
giving rise to physical conditions completely different and where different physical processes take over.<br />
In summary, the interplay of gas and grains plays a crucial role in the evolution of protostellar disks, and the<br />
collaboration between Astromol and FOST on this theme aims to address some specific aspects of this interplay.<br />
We take advantage of the complementary expertise of FOST group, mainly on the grains, and the Astromol<br />
group, mainly on the gas, to study the following four issues:<br />
1- The gas in the disk midplane: ionization <strong>de</strong>gree and the gas-to-dust ratio;<br />
2- The grain settling and role of small grains in heating the gas above the midplane;<br />
3- The gas and dust mixing processes;<br />
4- One specific aspect of the grain processing due to the X-rays emitted by the central source.<br />
Note that this collaboration extends to the group of C.Dominik in Amsterdam too, and has received financial<br />
support from the PAI “van Gogh” for the 2005 to 2007 (§2.7). In addition, we have started a collaboration with<br />
the people of the European Synchrotron Radiation Facility in <strong>Grenoble</strong> to study the chemistry on the grain<br />
62
Figure 3.7: Detection of HDO in the proto-planetary disk surrounding the solar type protostar DM Tau (Ceccarelli<br />
et al. 2005). The figure shows the HDO ground state transition at 464 GHz, which has been observed<br />
in absorption against the continuum emitted by the cold dust in the disk midplane. The fact that the line is in<br />
absorption implies that vapor water forms a blanket covering the entire disk of DM Tau.<br />
surfaces irradiated by X-rays. These experiments aim to simulate the conditions in the proto-planetary disks<br />
surrounding solar type protostars, which are known to be strong X-rays emitters (§3.2.6 and 3.2.7).<br />
In the incoming years, we plan to increase the Astromol involvement in the studies of the proto-planetary<br />
disks, notably their chemical and physical structure. This will also involve a more systematic use of the interferometric<br />
instruments (today Plateau <strong>de</strong> Bure, tomorrow ALMA), in addition to the already used millimeter<br />
and sub-millimeter single dishes (IRAM-30m, JCMT and CSO).<br />
Meanwhile, Astromol has obtained the following important results on the study of young gas rich protoplanetary<br />
disks:<br />
• The discovery of a way to probe the cold gas in the disk midplane. The midplane of the young protoplanetary<br />
disks that surround Sun-like protostars is so cold and <strong>de</strong>nse that all heavy-elements molecules,<br />
inclu<strong>de</strong>d CO, con<strong>de</strong>nse onto the grain mantles, disappearing from the gas phase. Since the bulk of the mass<br />
of the disk resi<strong>de</strong>s in the midplane, it is of paramount importance to have a way to probe this component,<br />
for studying how the disk evolves: the con<strong>de</strong>nsation of the dust, the dispersion of the gas, etc... Astromol,<br />
using the knowledge acquired in its studies on the molecular <strong>de</strong>uteration (§3.2.2), has proposed to observed<br />
the ground state transition of the H2D + molecular ion, and obtained the first <strong>de</strong>tections in 2004 (Ceccarelli<br />
et al. 2004). The H2D + observations not only provi<strong>de</strong> the first means to probe the disk midplane, but<br />
they also provi<strong>de</strong> a means to measure its ionization <strong>de</strong>gree, a key parameter in the theories of viscous<br />
accretion of proto-planetary disks (Ceccarelli & Dominik 2005).<br />
• The discovery of <strong>de</strong>uterated water vapor in proto-planetary disks. In general, water is a key molecule<br />
to observe, because it is a major actor in the cooling of the gas, as well as in its chemical composition.<br />
Deuterated water has the additional interest that the Oceans on the Earth are believed to be formed by the<br />
63
sublimation of water ice trapped either in comets or meteorites or, more in general, in the planetesimals<br />
which formed the Earth. A key parameter in these theories is the HDO/H2O ratio: in oceans it is ten<br />
times larger than the cosmic D/H elemental ratio, close to that of comets, and hundred times smaller than<br />
that observed in solar type protostars (§3.2.2). A big unanswered question is: what is the HDO/H2O in<br />
proto-planetary disks, which contain the material from which planetesimals, meteorites and comets are<br />
formed? Astromol has reported the first <strong>de</strong>tection of HDO in a proto-planetary disk (Fig. 3.7: Ceccarelli<br />
et al. 2005), from which a HDO/H2O ratio (∼ 1%) slightly lower than in protostars has been estimated.<br />
In<strong>de</strong>ed, the big contribution of these observations is that HDO in the measured quantities should have<br />
not been <strong>de</strong>tected, because H2O and HDO are believed to be almost totally frozen onto the grain mantles<br />
(at least in the region probed by the observations)! Since HDO has been observed, something is reinjecting<br />
water molecules from the grain mantles. Soon after the HDO <strong>de</strong>tection, Astromol showed that<br />
grain mantle photo-<strong>de</strong>sorption from the Interstellar UV field can in<strong>de</strong>ed keep the observed water column<br />
<strong>de</strong>nsity in the gas phase (Dominik, Ceccarelli, Hollenbach, Kaufman 2005, ApJL submitted).<br />
• The discovery of a small warm disk in a low mass binary system. By using Adaptive Optics (AO) ai<strong>de</strong>d<br />
2µm observations at Keck, we revealed the presence of a small ( ∼ < 5 AU), warm (∼ 400 K) and <strong>de</strong>nse ( ∼ > 10 7<br />
cm −3 disk surrounding the more massive companion of the binary system forming T Tau S (Duchene et<br />
al. 2005). The observations <strong>de</strong>tected the CO lines (from J=9 to J=20) in absorption against the source<br />
continuum, a technique already used by other authors for studying a (very) few other disk sources. The<br />
originality and importance of our observations is that, thanks to the coupling with the AO, we could study<br />
a close binary system and <strong>de</strong>monstrate that the disk of (at least) one of the two protostars is probably<br />
truncated because of the presence of the other protostar. We plan to carry out similar studies in a larger<br />
sample of sources, with the scope to un<strong>de</strong>rstand how, in<strong>de</strong>ed, the presence of a companion affects the<br />
circumstellar disks of the two composing protostars. More in general, the CO absorption technique is<br />
extremely powerful in characterizing the physical conditions of the gas in the warm layers of the protoplanetary<br />
disks, much more efficient than the mm/submm observations, which only provi<strong>de</strong> one CO J<br />
level at once.<br />
64
Chapter 4<br />
Perspectives<br />
4.1 Overview<br />
Astrochemistry is going to be the keyword of our research in the incoming years. Astrochemistry in its two<br />
major aspects: the molecular composition of the extra-terrestrial matter (§4.2.1) and the basic physical processes<br />
(§4.2.2) that govern it. In a more general context, our activity will expand to “touch” the new emerging research<br />
field of Exobiology, meant as the general study of life in the Universe. On this, our contribution will evi<strong>de</strong>ntly<br />
be on the Astrochemistry si<strong>de</strong>.<br />
The major new challenge that the Astromol team will face is the study of the molecular complexity in the<br />
interstellar space, and the basic processes linked to it: molecule i<strong>de</strong>ntification, formation, and evolution, with<br />
emphasis on during the star formation process, from the pre-collapse to the proto-planetary disk phase. This<br />
study will require substantial observational and theoretical progresses, and, consequently, a coordinated effort<br />
at the French, European and world level. Two new instruments, involving world wi<strong>de</strong> consortia, will allow<br />
those major observational leaps and are at the 2007-2010 horizon: Herschel and ALMA (§4.3). Besi<strong>de</strong>s, a large<br />
European coordinated effort is on progress to exploit at best the potentialities of both instruments: the EC<br />
FP6 network “The Molecular Universe” (§4.4). Astromol is heavily involved in those three large international<br />
projects, and our activity in the next 2007-2010 will be scientifically and practically dominated by that.<br />
In<strong>de</strong>ed, the Astromol scientific involvement in these three large projects is heavy, ambitious and important<br />
at the same time. It will require a substantial enlargement of the group to fulfill the engagements and, most<br />
important, to fully exploit all the potentiality of this involvement, which should allow to keep a leading position<br />
of Astromol in the relevant studies (§4.6).<br />
4.2 Scientific goals<br />
In the last four years, substantial progresses have been obtained in our un<strong>de</strong>rstanding of how stars, notably solar<br />
type stars, form. New signatures and processes of the early formation of solar type stars have been discovered:<br />
e.g. the extreme molecular <strong>de</strong>uteration, which accompanies the freezeout of the heavy-bearing molecules, and<br />
the birth of hot corinos in the interiors of the envelopes. However, many questions remain open. Here we<br />
mention what we consi<strong>de</strong>r some major open questions which Astromol can help to answer in the next years to<br />
come.<br />
From a chemical point of view, it is totally unclear what is the ultimate molecular complexity reached during<br />
the proto-stellar phase. Do pre-biotic or even biotic molecules form? In what quantity? How? From a chemical<br />
and evolutionary point of view, it is even less clear what is the fate of these and any other molecules formed<br />
during the protostellar phase. Do they survive the proto-planetary disk phase? Are they incorporated into the<br />
forming and/or formed planets, via for example bombardment by comets and asteroids? In what quantity?<br />
How?<br />
65
If the chemistry in the first phases of the collapse seems to reach a high level of complexity and sophistication,<br />
much less is known about the chemistry in the proto-planetary disks. At present, only a very few and basic<br />
molecules have been <strong>de</strong>tected (CO, CN, HCO + ...) and in a very few objects. Whether new molecules form in<br />
this phase, either in the gas phase or grain surfaces, is almost totally unknown. Chemistry in proto-planetary<br />
disks is <strong>de</strong>finitively a challenge for the incoming years, and we intend to take on this challenge.<br />
Also, basic questions about the interaction between the forming star and the surrounding environments<br />
remain open. What is the effect of the X-ray/UV irradiation on the circumstellar material? Are the outflows<br />
from the central star only <strong>de</strong>structive? At what level do they contribute to the molecular complexity? What are<br />
the basic physical processes occurring when the outflowing material encounter the surrounding parent cloud?<br />
Answering all these very basic and important questions require:<br />
i) acquiring new, more sensitive observational data;<br />
ii) <strong>de</strong>veloping new, more sophisticated astrophysical mo<strong>de</strong>ls;<br />
iii) carrying out new, more complex computations of basic molecular physics.<br />
The next two subsections will <strong>de</strong>scribe in some <strong>de</strong>tail the expected new directions and <strong>de</strong>velopments of<br />
our research activity. The two subsections will address the “Star Formation” and “Molecular Physics” themes<br />
respectively.<br />
4.2.1 Star Formation<br />
The overall goal is the study of the molecular complexity during the formation of solar type protostars. More<br />
specifically, we plan to <strong>de</strong>velop the following four major lines of research:<br />
1. Molecular Deuteration in the ISM, pre-stellar cores, and protostars/ In the last few years our group has<br />
had a leading role in the study of the molecular <strong>de</strong>uteration. Also thanks to our contribution, substantial<br />
progresses have been achieved and the basics processes leading to the observed extreme <strong>de</strong>uterations is<br />
now (probably) mastered. Therefore, the era of “using” this knowledge to study the relevant physical<br />
processes during the star formation phase as well as in other astronomical sources, even to extra-galactic<br />
in CO <strong>de</strong>pleted<br />
sources, is open. Notably examples are the diagnostic value of the <strong>de</strong>uterated forms of H + 3<br />
regions, like the center of the pre-stellar cores or the midplane of the young proto-planetary disks. In the<br />
formers, these molecules permit to study the motion, and whether, when and how the collapse sets in. In<br />
the latter, H2D + and HD + 2 allow to measure the ionization <strong>de</strong>gree and the dust to gas ratio (item 3).<br />
2. Molecular Complexity in hot corinos. The existence of the hot corino has been <strong>de</strong>monstrated just in the<br />
last two years, mostly by the works of our group, in collaboration with WAGOS (§2.7) and people of<br />
IRAM (for the studies with the Plateau <strong>de</strong> Bure Interferometer). Very little is known so far, because<br />
these objects are difficult to observe, being compact and faint in the lines. The incoming four years<br />
will certainly see an explosion of these studies worldwi<strong>de</strong>, both on observational and theoretical si<strong>de</strong>, on<br />
this subject. Our scope is to keep a prominent role in this field by expanding both our mo<strong>de</strong>ling and<br />
observing capacities. It will be a challenge, because several groups have entered the race on this subject<br />
(<strong>de</strong>monstrating its interest), but we have the right expertise to take this challenge. We are involved, and<br />
often with a major role, in major projects worldwi<strong>de</strong> to obtain the full census of the molecular lines in solar<br />
type protostellar objects: the “Unbiased Spectral Survey of IRAS16293-2422” in the IRAM, JCMT and<br />
APEX bands; the “Spectral Survey of Star Forming Regions Legacy Project” at JCMT; the Herschel-HIFI<br />
Key Program “Spectral Surveys of Star Forming regions” (see <strong>de</strong>tails in §4.3). These surveys will allow<br />
to have a complete view of the chemical composition of the solar type protostars and their surroundings<br />
in some cases. In addition, they will allow studies of the kinematics and <strong>de</strong>tailed physical structure across<br />
the regions, thanks to the peculiarity of the chemical composition and line excitation, different in different<br />
regions. In addition, we have embarked in the systematic study of the hot corino at high spatial resolution<br />
with PdBI, to probe and measure their sizes and molecular content. In summary, the incoming years will<br />
see likely a change of these studies from pioneer to fully established, and our group is in a good position<br />
to be a major actor in this play.<br />
3. Proto-planetary Disks. We plan to invest more and more in this field. In particular, we have new lines<br />
of research that we intend to pursuit, as <strong>de</strong>tailed in the following. i) We have shown that the <strong>de</strong>uterated<br />
forms of H + 3 (notably the ground state transition of H2D + ) can be used to measure the ionization <strong>de</strong>gree<br />
66
in the midplane of young disks surrounding solar type protostars and their dust to gas ratio, two key<br />
parameters in the theories of disk evolution and planet formation. This is a very recent result, and we<br />
certainly plan to fully exploit this new line of research, by carrying out systematic surveys, both with<br />
single dish telescopes and mo<strong>de</strong>ling. So far CSO, SMA (since spring 2005) and APEX (since October 2005)<br />
permit these observations, but in a not too far future the ortho-H2D + line used for these studies will be<br />
accessible with ALMA. In addition, the para-H2D + , as well as both ortho and para lines of HD + 2<br />
will also<br />
be accessible with the advent of Herschel HIFI and SOFIA. ii) The <strong>de</strong>tection of <strong>de</strong>uterated water by our<br />
group has also open a new way to probe the history of the dust grains, and specifically the fate of their icy<br />
mantles during the proto-planetary phase. Again, this is a field just started and that clearly <strong>de</strong>serves a full<br />
exploitation. One by-product is the prediction of the observability of water vapor in proto-planetary disks<br />
with Herschel, observations which will become available in the incoming four years. iii) More in general,<br />
we plan to expand our observational and mo<strong>de</strong>ling capabilities on the chemistry of proto-planetary disks,<br />
by applying, exporting and expanding what we have learned so far in the studies of the previous phases.<br />
Notable examples are the chemistry of sulfur, oxygen and carbon in proto-planetary disks, which haven’t<br />
been exploited so far, and on which we have a good expertise.<br />
4. The interaction of the forming star with the surroundings: outflows and X-rays Our group is currently<br />
investing stronger efforts in the studies on protostellar outflows. The emphasis is put on both the observational<br />
and theoretical si<strong>de</strong>s. Observationally, the goal is to <strong>de</strong>termine the physical conditions (velocity,<br />
<strong>de</strong>nsity, temperature) in the entrained gas and in the shock regions, based on the H2 line emission, accessible<br />
in the mid- and near-IR, and the emission of the high-excitation line of molecular tracers in the<br />
mm/submm windows. Theroretically, it is necessary to improve the existing mo<strong>de</strong>ls to a) reach a multidimensional<br />
(2D/3D) <strong>de</strong>scription, required to provi<strong>de</strong> a realistic treatment of the leading bow in outflows,<br />
b) make predictions not only on the (velocity-integrated) line flux but on the line profiles. These aspects<br />
are un<strong>de</strong>rtaken in collaboration with colleagues at LERMA in Paris (G. Pineau <strong>de</strong>s Forets, S. Cabrit)<br />
and at DAMIR in Madrid (J. Cernicharo, J. Martin-Pintado). A large-scale survey of the CO emission<br />
in TMC 1 has been un<strong>de</strong>rtaken, in collaboration with IRAM colleagues (K. Schuster, C. Thum) to search<br />
in an unbiased way for molecular outflows and their protostars, down to the smallest scale size, comparable<br />
to the cooling lengthscale in MHD shocks (10 16 cm), and investigate their impact on the global star<br />
formation in the cloud.<br />
5. X-rays: from astronomy to the laboratory<br />
• Among the unsolved questions is the problem of the X-ray emission from the youngest protostars (socalled<br />
Class 0, still in a state of gravitational collapse). Up to now, and in spite of extensive searches on<br />
∼ 20 low-mass star-forming regions, no Class 0 protostar has been <strong>de</strong>tected in X-rays (Montmerle et al.,<br />
in preparation). This is most likely due to the fact that the extinction of their <strong>de</strong>nse envelopes is very high<br />
(AV > 500). With a careful summing of existing XMM and Chandra observations, it is however hoped to<br />
at least set stringent upper limits to the intrinsic X-ray luminosity. Another way to attack the problem<br />
is, here also, to look for indirect evi<strong>de</strong>nce in the mm range, in the form of specific radicals (like HCO +<br />
or DCO + ) that could be the signature of internal X-ray irradiation. Except perhaps in one case, IRAS<br />
16293 (see Ceccarelli et al. 2002b), no evi<strong>de</strong>nce was found so far and more observations are planned. Here<br />
again, the ultimate goal is to measure the ionization fraction of the envelope and the resulting coupling<br />
between the material and magnetic fields.<br />
Similar observations will be conducted in and around more evolved sources, from evolved protostars (Class<br />
I) to T Tauri stars still embed<strong>de</strong>d in molecular clouds, for which the X-ray luminosity is measured and<br />
can be compared with chemical tracers of irradiation.<br />
• Another approach is to do laboratory experiments. Several years ago, T. Montmerle co-supervised a<br />
PhD thesis (S. Gougeon, 1998) which featured X-ray irradiation experiments on mo<strong>de</strong>l interstellar dust<br />
grains (PAHs, coals, etc.) using the ESRF facility in <strong>Grenoble</strong>, to compare with ISO data in star-forming<br />
regions. The laboratory IR spectra from irradiated grains proved to be complex and difficult to interpret,<br />
but revealed many interesting features (like spectral lines associated with certain bonds like C-C, C-H,<br />
etc.), some evolving with the irradiation dose, others not. On the other hand, the X-ray energies at ESRF<br />
(nearly 10 keV) tend to be high with respect to typical stellar energies (a few keV), precluding a direct<br />
comparison with astronomical data. It is envisaged in the current prospective period (2007-2010), to set<br />
up follow-up experiments at the SOLEIL facility, which offers softer X-rays, and compare the resulting IR<br />
spectra with mo<strong>de</strong>rn, more sensitive astronomical IR spectra such as obtained by Spitzer.<br />
Along the same lines, a fruitful collaboration with French meteoriticists and experimentalists (e.g., M.<br />
Gounelle from Orsay, M. Chaussidon from Nancy, H. Leroux from Lille, possibly also E. Quirico from<br />
LPG) has been established, with the aim of fe<strong>de</strong>rating experiments in various related fields of astrophysical<br />
interest nationwi<strong>de</strong> (approved proposal to PNPS).<br />
67
4.2.2 Molecular Physics<br />
The theoretical advances ma<strong>de</strong> by our group during the past four years have been mainly focused on low-energy<br />
excitation processes involving small polyatomic molecules in collisions with H2 and electrons. In addition to their<br />
astrophysical relevance, our works have provi<strong>de</strong>d significant advances of broad interest in molecular physics.<br />
The next challenges we whish to address are relevant to higher temperature processes and larger molecules. This<br />
evolution of our theoretical activity naturally follows the current trend of observing more and more complex<br />
molecules in more and more “harsh” astronomical environments.<br />
1. Ro-vibrational excitation A particular challenging issue of current collisional studies is the computation of<br />
rovibrational rates for polyatomic species. These rates become astrophysically relevant at relatively high<br />
temperature (typically above 300 K) where a large number of rovibrational quantum channels open up.<br />
Thus, even for a light molecule like water, the calculation of rovibrational cross sections at the relevant<br />
energies is currently computationally impossible at the close-coupling “exact” level of theory. Furthermore,<br />
approximate quantum methods such as the wi<strong>de</strong>ly used vibrational close-coupling rotational infiniteor<strong>de</strong>r-sud<strong>de</strong>n<br />
(VCC-IOS) approximation are questionable for molecules with relatively large rotational<br />
constants, as we have shown for water in a recent paper (Faure et al., JCP 2005). The reliability of<br />
standard quantum/classical approximations must therefore be assessed and controlled in a number of<br />
representative cases. In this context, we note that H2O and HC3N are two very interesting candidates as<br />
they present both very different rotational constants and vibrational frequencies. As a result, our next<br />
short-term theoretical efforts will be put on the treatment of the rovibrational dynamics of these and other<br />
larger systems.<br />
In addition to these <strong>de</strong>velopments, the relevance of rovibrational processes in actual astronomical sources<br />
must also be investigated. Our preliminary results for H2O−H2 (Faure et al. 2005) have thus shown that<br />
the collisional excitation of the bending mo<strong>de</strong> of water should be efficient only for <strong>de</strong>nsities larger than<br />
about 10 10 cm 3 s −1 . Such high <strong>de</strong>nsities are found for example in the envelopes of late-type stars. For other<br />
molecules with low vibrational frequencies, however, critical <strong>de</strong>nsities should be significantly lower. As a<br />
first step, qualitative investigations based on the expected or<strong>de</strong>rs of magnitu<strong>de</strong> should thus help to clarify<br />
the relevance of the various collisional processes in environments of mo<strong>de</strong>rate to high temperatures.<br />
2. Heterogeneous reactivity In spite of numerous recent experimental and theoretical studies, grain surface<br />
chemistry is still far more poorly un<strong>de</strong>rstood than gas-phase chemistry, notably because of our lack of a <strong>de</strong>tailed<br />
knowledge of the physical nature of the surface. The two major problems faced by astrochemists are<br />
currently: (i) the <strong>de</strong>tailed mechanisms for the sticking/reaction/<strong>de</strong>sorption processes on low-temperature<br />
interstellar surfaces and (ii) the <strong>de</strong>pen<strong>de</strong>nce of these processes on the morphology and structure of the<br />
grains. Given the high dimensionality of these dynamical problems, classical dynamics simulations are<br />
particularly suited. Quantum effects such as tunneling un<strong>de</strong>r diffusive barriers might however prove crucial<br />
for some reactive processes at very low temperature. Inclusion of “local” quantum effects in large-scale<br />
classical simulations is thus a major issue we wish to address in the upcoming years. The specific astrophysical<br />
problems we wish to tackle are directly related to recent observational results of our group: (i)<br />
how hydrogenated molecules (H2O, H2CO, CH3OH, etc.) form on grain surfaces? (ii) how different is<br />
it for <strong>de</strong>uterated species? (iii) what processes govern the <strong>de</strong>pletion of molecules like CO and N2 in cold<br />
pre-stellar cores?<br />
In addition to these theoretical <strong>de</strong>velopments, the possibility of carrying out original experiments on<br />
interstellar ice analogs has been recently discussed with Bernard Schmitt and Eric Quirico, specialists of the<br />
synthesis, characterisation and properties of ices of planetary interest at the <strong>Laboratoire</strong> <strong>de</strong> Planétologie<br />
<strong>de</strong> <strong>Grenoble</strong>. A collaborative project might be structured around the sticking and <strong>de</strong>sorption processes at<br />
work in the cold interstellar medium.<br />
3. Towards larger molecules : far infra-red or micro-wave ? While the observation of small molecules, 2<br />
to 6–10 atoms is now routine (from OH to (CH3)2O or HC7N) there is a natural ten<strong>de</strong>ncy to look for<br />
larger molecules, comprising cycles or several functionalities. The obvious goal is to get nearer and nearer<br />
to molecules of great chemical importance (like 5-membered or 6-membered heterocycle) or molecules<br />
pertain to biochemistry, like sugars, amino-acids, . . . Observing these molecules is rather difficult today,<br />
for several, not mutually exclusive, reasons: (i) Evi<strong>de</strong>ntly their abundances are small (ii) Being heavy<br />
molecules, their rotational constants are small and they are usually asymmetric tops; consequently their<br />
rotational lines for mo<strong>de</strong>rate J lie very low in frequency in domains that may be not so well explored<br />
(iii) The oscillator strength is divi<strong>de</strong>d into many low frequency lines, ren<strong>de</strong>ring the observations all the<br />
68
more difficult (iv) The region where the highly excited J lines fall may be congested and these spectra<br />
are sometimes not known experimentally, at least with high precision at high J.<br />
Another path leading to the observation of large molecules comes from the far infrared spectral region<br />
(ν ∼ 0.5 · · · 2 THz, k ∼ 15 · · · 60 cm −1 ). This range of frequency corresponds to floppy bending mo<strong>de</strong>s or<br />
torsional mo<strong>de</strong>s. Some are experimentally known but most are not. The advantage of the THz mo<strong>de</strong>s s<br />
their higher frequency, leading to higher A Einstein coefficients, hence higher sensitivity. Also, it is possible<br />
that congestion problems would be less severe. These consi<strong>de</strong>rations remain however still speculative and<br />
necessitate a joint theoretical and experimental effort (the Soleil light source may be very valuable).<br />
A new generation of out of atmosphere telescopes, and principally Herschel (HIFI instrument) will open<br />
this spectral window. It is essential that our team takes part in the large molecule search that these<br />
instrument will allow.<br />
4. Gas-phase reactivity: revisiting reaction rates Large mo<strong>de</strong>ls of gas phase chemistry have been only partially<br />
tested in their various aspects. Here we mention some major issues:<br />
• What is the relevance of present-day rates, is it worthwhile to compute some with a good precision?<br />
Many rates are guessed from analogous reactions. How important is it to know the rate evolution<br />
with temperature, in particular for neutral-neutral reactions.<br />
• What is the structural stability of the differential equation system that governs the evolution of<br />
species populations. Some work in this realm has been un<strong>de</strong>rtaken by V. Wakelam.<br />
• How interesting is it to simplify system and analyze some carefully chosen subsystem ?<br />
An interaction with specialists in dynamical systems theories would be particularly useful. In this context,<br />
Astromol (LW, PV, AF) received PCMI financial support for leading en effort in this field.<br />
5. Transition state theory (TST) Many theoretical problems remain open, most of which with important<br />
applications in theoretical chemistry but also in celestial dynamics. In particular, progress must be ma<strong>de</strong><br />
in TST for chemical reactions on surfaces or with many <strong>de</strong>grees of freedom.<br />
4.3 The involvement in the large international projects: Herschel<br />
and ALMA<br />
Astromol is heavily involved in two big international projects, <strong>de</strong>fined as major milestones for the French<br />
Astronomy: the European satellite Herschel Space Observatory (HSO) and the sub-millimeter interferometer<br />
ALMA. The two projects will start working in the next few years: Herschel in 2008, and ALMA soon after.<br />
Before the instruments become operative, Astromol is actively participating to and will continue to work on<br />
their preparation.<br />
More specifically, members of Astromol are official or unofficial co-Astronomers of the HIFI consortium.<br />
They are participating to the preparation of a Key Program of Herschel, entitled “Spectral Line Surveys of<br />
Star Forming Regions” (requiring about 300 hours of HIFI Guaranteed Time). The program consists in the<br />
observation of the entire (or most) spectral band of HIFI, at the highest possible spectral resolution (∼ 1 km/s),<br />
of a number of representative sources of star formation. The Key Program is lea<strong>de</strong>d by a member of the Team<br />
(C.Ceccarelli). Table 4.1 summarizes the involvement of Astromol in this program. Note that C.Ceccarelli is<br />
also the lea<strong>de</strong>r of the “HIFI Star Formation Group”, which proposes three HIFI Key Programs: “The water in<br />
Star Forming Regions”, “Orion and SgrB2 Star Formation Regions with HIFI”, and the “‘Spectral Line Surveys<br />
of Star Forming Regions” already mentioned.<br />
After the launch of Herschel, Astromol will be evi<strong>de</strong>ntly very active in the exploitation of the data. In<strong>de</strong>ed,<br />
we expect that this will be a major involvement for our group, and even a challenge, for the amount of expected<br />
data and information. To give an i<strong>de</strong>a, based on the ground-based observations, we expect to <strong>de</strong>tect around 10<br />
lines per GHz ,in the Class 0 source IRAS16293-2422. On the ∼ 1500 GHz band of HIFI this will provi<strong>de</strong> ∼ 10 4<br />
lines from different molecules! Evi<strong>de</strong>ntly, this is a major challenge. Two aspects make it a “major challenge”:<br />
i) the handling of such a massive amount of data; ii) the interpretation of so many lines, many of which from<br />
molecules whose physical proprieties have not yet fully studied. Our group is already preparing itself for this<br />
challenge, <strong>de</strong>veloping the procedures to handle all this information in an efficient way.<br />
69
Source Herschel Time Astromol<br />
Class (hours) members<br />
Pre-Stellar Core 25 CC, BL<br />
Class 0 low mass 50 CC, BL<br />
Class 0 intermediate mass 50 CC, BL<br />
Outflows 30 BL, CC<br />
Table 4.1: Herschel HIFI Key Program “Spectral Line Surveys of Star Forming Regions”<br />
. Summary of the scientific topics, and the amount of Herschel guaranteed time <strong>de</strong>voted to each of them. The<br />
third column lists the participation of Astromol members to each topics: CC=C.Ceccarelli, BL: B.Lefloch.<br />
In this respect, Astromol is involved in the project “Unbiased Spectral Survey of the solar type protostar<br />
IRAS16293-2422” (lea<strong>de</strong>d by E. Caux, CESR Toulouse), for which about 300 hours of IRAM and JCMT time<br />
have been allocated (and used). Also, Astromol is involved in the JCMT Legacy Program “Spectral Line Surveys<br />
of Star Forming Regions” (lea<strong>de</strong>d by G.Fuller, Manchester, UK) which has been allocated about 200 hours.<br />
In addition, a key aspect in this preparation is the participation to the European Network “The Molecular<br />
Universe”, <strong>de</strong>scribed below (§4.4). Note that, Herschel HIFI and ALMA are very complementary instruments.<br />
Much of what we are <strong>de</strong>veloping and learning for Herschel HIFI will also be useful in the exploitation of ALMA,<br />
and our group will not make this opportunity to be spoiled. To support our statement, in the last year we have<br />
been <strong>de</strong>veloping a tighter collaboration with people at IRAM, notably the collaboration with Roberto Neri on<br />
the exploitation of the Plateu <strong>de</strong> Bure to observe organic molecules in young embed<strong>de</strong>d protostars as well as in<br />
disks (as evi<strong>de</strong>nt from the list of publications of our group).<br />
4.4 The European Network “The Molecular Universe”<br />
The RTN FP6 European Network “Molecular Universe” has been fun<strong>de</strong>d for 2005-2008 with the following<br />
ambitious objectives: “This highly interdisciplinary network combines European researchers from 9 countries and<br />
21 laboratories in the areas of laboratory spectroscopy, laboratory astrochemistry, molecular quantum mechanical<br />
studies, astronomical mo<strong>de</strong>llers, and experts on data bases and web interfaces. By training future researchers<br />
and by integrating European research efforts in the field of molecular astrophysics, Europe will be well poised<br />
to take advantage of the planned European ground-based (such as Bure extensions and ALMA) and space-based<br />
missions (such as Herchel-HIFI).”<br />
France is strongly represented in this network, thanks to the active PCMI community. And among the<br />
French groups, Astromol is highly involved.<br />
In Task 1, “Molecular Complexity in Space”, we are involved in the three topics and in 11 milestones.<br />
Namely for Topic 1.1, “Water in the Universe”, we are involved in milestones 1.1.2 to 1.1.7:<br />
• 9D-Surface + rotational cross sections of H2O + H2<br />
• 6D-Surface + rotational cross section of H2O + H/He<br />
• Ro-vibrational cross-sections H2O + H/He/H2<br />
• Ro-vibrational cross sections of HDO + H/He/H2<br />
• Experimental measurement of state-to-state cross-sections for H2O + H2 and probing theoretical predictions<br />
• Radiative transfer and excitation of H2O emission in photon dominated regions<br />
Then for Topic 1.2, “Carbon Chemistry”, we are involved in milestone 1.2.8:<br />
• Ab-initio intra and inter molecular interactions for HC3N and dynamics<br />
For Topic 1.3, “Deuterium chemistry”, we are involved in milestones 1.3.3, 1.3.4, 1.3.6, and 1.3.7:<br />
70
• 12D-Surface of NH3 with H2<br />
• Rotational excitation of NH2D, ND2H with H2<br />
• Experimental measurement and theoretical predictions of cross-sections for NH2D + H2<br />
• Surface of H2CO with H2 for excitation studies of HDCO / H2CO<br />
In Task 2, “Chemistry in Regions of Star Formation”, one of us (CC) is the task manager of the network,<br />
and we are also involved in Topic 2.2, “Nitrogen Chemistry as tracers of protostellar con<strong>de</strong>nsation” for milestone<br />
2.2.7:<br />
• Sticking and <strong>de</strong>sorption processes in dark cloud/proto-stellar mo<strong>de</strong>ls: impact on gas abundances and<br />
ionization state<br />
Finally in Task 3, “Databases and Web interfaces”, we are involved in milestone 3.2:<br />
• Simulation tool combining astrophysical mo<strong>de</strong>ls and molecular data bases to produce synthetic spectra<br />
for comparison with observations<br />
Obviously the fulfillment of our commitments in the Molecular Universe network constitutes a large fraction<br />
of the prospective of the Astromol team until the end of 2008.<br />
We also plan to extend our contributions to milestone 3.2 to applications related to the Virtual Universe.<br />
In particular, as already previously explained, we plan to <strong>de</strong>velop original services for coupling the VO grid<br />
to computer grids, and thus facilitate the systematic exploration of astrophysical mo<strong>de</strong>ls on a wi<strong>de</strong> range of<br />
objects selected by the VO requests.<br />
4.5 Cosmology: a new frontier for Astromol ?<br />
Cold interstellar dust and cosmology have a large interplay in the millimetre electromagnetic spectrum. Synergy<br />
between these two fundamental fields in astrophysics (one’s signal is the noise source of the other) is also found<br />
in instrumental, observational and data reduction techniques.<br />
In the star formation process, one of the main topics in astrophysics, dust is both acting in it and tracing<br />
it. Acting in it, because dust can evacuate some of the gravitational energy in some phases of the pre-stellar<br />
collapse and dust is strongly coupled with the interstellar molecular gas, a central topic of Astromol. Tracing<br />
the star formation process, because mo<strong>de</strong>rn instrumentation, basically cold bolometers in the (sub)millimetre<br />
domain, allows us to map dust, hence gas, with an equivalent column <strong>de</strong>nsity as low as 10 22 H m −2 .<br />
In the course of the present activity period, F.-X. Désert continued working on bolometer <strong>de</strong>velopments<br />
in preparation for the Archeops balloon mission, to study the submm emission of the whole sky, with two<br />
main constituents: (i) a foreground galactic dust emission; (ii) a cosmological microwave background (CMB),<br />
basically at 3 K but with minute dust emission fluctuations (∆T ∼ 10 −4 at a few 100 GHz) tracing the earliest<br />
episo<strong>de</strong>s of galaxy formation in the recombination era.<br />
While was F.-X. Désert formally belonging to the Sherpa group in the previous LAOG structure, it became<br />
evi<strong>de</strong>nt from this work that he should eventually join the Astromol group, for at least two reasons. First,<br />
while mainly <strong>de</strong>voted to comological objectives, the Archeops mission is also rich in galactic dust astrophysics<br />
implications (Benoît et al. 2004), and more generally, on cosmic dust in a variety of environments (submm<br />
excess in the CMB possibly caused by dust created and ionized by Population III stars: Elfgren & Désert 2004).<br />
Second, the associated instrumental work on bolometers is also in the submm range, and prepares for the High<br />
Frequency Instrument (HFI) on Planck i.e., the companion satellite to Herschel used by the Astromol group.<br />
This instrument inclu<strong>de</strong>s a dilution cooling system ma<strong>de</strong> in <strong>Grenoble</strong> (Air Liqui<strong>de</strong> and CRTBT), allowing<br />
to obtain high resolution all-sky maps of cold dust with unprece<strong>de</strong>nted sensitivity. In collaboration with<br />
CRTBT and LPSC in <strong>Grenoble</strong>, and with the whole Archeops team, we are completing the publication of<br />
71
several important studies that anticipate the harvest of Planck results: 1) polarization of the emission of diffuse<br />
interstellar dust, 2) anomalous dust emissivity and 3) a catalogue of about a hundred (13 arcmin size) bright<br />
point sources. These results were obtained from a 12-hour Archeops balloon flight in the Arctic sky in 2002,<br />
using HFI technology (Benoît et al. 2003a, b; Tristram et al. 2005)<br />
The Planck satellite will allow the ultimate measurements of CMB anisotropies with a sensitivity about ten<br />
times better than the WMAP achievement and an angular resolution 3 times better. An accurate <strong>de</strong>termination<br />
to within one percent will be obtained for the ten or so cosmological parameters <strong>de</strong>scribing our Universe (Hubble<br />
constant, curvature, cold, neutrino, and baryonic matter content, dark energy and its equation of state,...). We<br />
are involved in the ground-based and in-flight calibration of HFI as well as in some data processing pipeline, in<br />
collaboration with other <strong>Grenoble</strong> laboratories (Santos-Renault team at LPSC, Benoît-Camus team at CRTBT).<br />
In the coming years, we intend to make an optimal use of the Archeops then Planck submillimetre maps<br />
for in-<strong>de</strong>pth scientific results. In the mean time, we take part in the <strong>de</strong>velopments of new CCD-like bolometer<br />
cameras, in particular for the IRAM 30m telescope (the program DCMB, led by A. Benoît, is fun<strong>de</strong>d by INSU,<br />
PNC, PN Astroparticules and CNES). These cameras could provi<strong>de</strong> a useful complementary tool to the space<br />
experiments (Herschel, Planck) and Alma which will all arrive between 2007 and 2012.<br />
4.6 The needs of Astromol : accretion and recruitment<br />
Our plans are admittedly scientifically very ambitious. Our scientific record endorses our ambitions, and pushes<br />
us towards far reachable goals. However, to fully exploit the capacities and knowledges we have <strong>de</strong>veloped so<br />
far, and to keep having a leading role in our research lines, we evi<strong>de</strong>ntly need to become bigger in terms of<br />
permanent and not-permanent staff, and not by a number of one. We aim to enlarge our group by accreting<br />
senior researchers and, possibly Post-Docs (which, as known, are extremely rare in France). However, there is<br />
an evi<strong>de</strong>nt need to increase the number of permanent stuff members by hiring young researchers. In the past we<br />
have been forming several of them, and good candidates are in<strong>de</strong>ed available. To be more specific, the following<br />
major areas require urgently young permanent researchers in the next four years (of this quadriennal):<br />
• At the short horizon 2006-2010, we have the big challenge of being able to scientifically fully exploit the<br />
opportunity we have been creating for ourselves and France of the Herschel HIFI Key Program “Spectral<br />
Line Surveys of Star Formation Regions”. Note that this is the largest Herschel HIFI Key Program in<br />
terms of hours lea<strong>de</strong>d by a French researcher and with the largest amount of French HIFI Guaranteed<br />
Time. We feel therefore mandatory for us to make it a scientific success. While we have been <strong>de</strong>veloping all<br />
the important tools to exploit at best this occasion (involvement in “The Molecular Universe” European<br />
Network -§4.4-, spectral surveys with ground based millimeter and sub-millimiter telescopes -§4.3-...),<br />
there is clearly an urgent need of accretion in terms of permanent staff. Specifically, we need to hire<br />
two young researchers with experience in molecular line emission, line i<strong>de</strong>ntification and mo<strong>de</strong>ling of<br />
protostellar environments, the first as soon as possible (2006/2007), to participate to the preparation of<br />
the programs (doing observations, mo<strong>de</strong>ling and interpretation of the data), and the second one once<br />
Herschel has launched (2008/2009) to reinforce Astromol in the exploitation of the Herschel HIFI data.<br />
• The physics and chemistry of the proto-planetary disks is a hot field of research where LAOG has a<br />
prominent position in the international community. Astromol entered this field of research only recently,<br />
but with successes which authorize ambitious plans (§3.5). In addition, the proto-planetary disks is<br />
also a theme of research of the FOST team, and the interplay between the two teams has been already<br />
very fruitful. This and the complementarity of the different observational tecniques (from X-rays to IR<br />
to radio observations) makes LAOG a privileged and unique site in France for <strong>de</strong>veloping this line of<br />
research, notably the chemistry in proto-planetary disks. However, in or<strong>de</strong>r to capitalize and expand the<br />
Astromol activity on the proto-planetary disk field of research, Astromol needs additional manpower, and<br />
particularly on the mo<strong>de</strong>ling of the chemistry.Consi<strong>de</strong>ring the timescale of the evolution of our research,<br />
we envisage that a young researcher will be in <strong>de</strong>mand by 2007/2008.<br />
• In the context of the ALMA exploitation, IRAM collaboration and the LAOG-IRAM European Center of<br />
Expertise for Interferometry in Astronomy (CEXIA: see Executive Summary) Astromol is strongly solicited<br />
to take a major role, as it is the natural interlocutor with IRAM and its research heavily does and will<br />
use millimeter (and submillimeter) interferometric facilities. Again, Astromol has in<strong>de</strong>ed the capacities<br />
72
for doing that, but we are limited by the limited manpower we dispose. In or<strong>de</strong>r to appropriately answer<br />
to the <strong>de</strong>mand, the hiring of a young researcher expert in interferometry is required by 2008/2009.<br />
73
Chapter 5<br />
Selected Publications<br />
• Discovery of Deuterated Water in a Young Protoplanetary Disk<br />
Ceccarelli, C.; Dominik, C.; Caux, E.; Lefloch, B.; Caselli, P.<br />
Astrophysical Journal Letters 2005, 631, L81<br />
• Faure, Alexandre; Valiron, Pierre; Wernli, Michael; Wiesenfeld, Laurent; Rist, Claire; Noga, Josef; Tennyson,<br />
Jonathan<br />
A full nine-dimensional potential-energy surface for hydrogen molecule-water collisions<br />
Journal of Chemical Physics 2005, 122, 221102<br />
• Shock-induced PDR in the Herbig-Haro object HH 2<br />
Lefloch, B. ; Cernicharo, J.; Cabrit, S.; Cesarsky, D.;<br />
Astronomy and Astrophysics 2005, 433 ; 217-227<br />
• Improved algorithm for triple-excitation contributions within the coupled cluster approach<br />
Noga, J.; Valiron, Pierre<br />
Molecular Physics 2005, 103, 2123-2130<br />
• Geometry of phase-space transitions states: many dimensions, angular momentum.<br />
Wiesenfeld, L.<br />
Adv. Chem. Phys. 2005, 130A, 217<br />
• Near-Arcsecond Resolution Observations of the Hot Corino of the Solar-Type Protostar IRAS 16293-2422<br />
Bottinelli, S.; Ceccarelli, C.; Neri, R.; Williams, J. P.; Caux, E.; Cazaux, S.; Lefloch, B.; Maret, S.;<br />
Tielens, A. G. G. M.<br />
Astrophysical Journal Letters 2004, 617, L69<br />
• Detection of H2D+: Measuring the Midplane Degree of Ionization in the Disks of DM Tauri and TW<br />
Hydrae<br />
Ceccarelli, C.; Dominik, C.; Lefloch, B.; Caselli, P.; Caux, E. Astrophysical Journal Letters 2004, 607,<br />
L51<br />
• The H2CO abundance in the inner warm regions of low mass protostellar envelopes<br />
Maret, S.; Ceccarelli, C.; Caux, E.; et al.<br />
Astronomy and Astrophysics 2004, 416, 577<br />
• Electron-impact rotational excitation of water<br />
Faure, Alexandre; Gorfinkiel, Jimena D.; Tennyson, Jonathan<br />
MNRAS 2004, 347, 323<br />
• CO Depletion and Deuterium Fractionation in Prestellar Cores<br />
Bacmann, A.; Lefloch, B.; Ceccarelli, C. ; Steinacker, J.; Castets, A.; Loinard, L.;<br />
Astrophysical Journal Letters 2003, 585 ; L55-L58<br />
• A Keplerian disk around the Herbig Ae star HD 34282<br />
Pietu, V., Dutrey, A., Kahane C.<br />
Astronomy and Astrophysics 2003, 398, 565<br />
74
• Determination of the gas-to-dust ratio in nearby <strong>de</strong>nse clouds using X-ray absorption measurements<br />
Vuong, M. H.; Montmerle, Thierry; Grosso, Nicolas; Feigelson, E. D.; Verstraete, L.; Ozawa, H.<br />
Astronomy and Astrophysics 2003, 408 ; 581<br />
• Rotational transition states: relative equilibrium points in inelastic molecular collisions<br />
Wiesenfeld, L.; Faure, A.; Johann, T.<br />
Jour. Ph.B 2003, 36, 1319<br />
75
Part IV<br />
TEAM FOST<br />
The first image of a planetary mass companion outsi<strong>de</strong> our solar system, observed with<br />
NAOS on the VLT<br />
77
Chapter 6<br />
Introduction of the team & Science<br />
Results<br />
6.1 FOST: a large research group on the formation of Stars and<br />
Planets, and the Lower Mass Function<br />
Since the last review committee visited LAOG, three groups joined efforts to form what is now known as team<br />
FOST. FOST is an acronym standing for “FOrmation Stellaire, objets SubStellaires, and Systèmes planéTaires”,<br />
that is often contracted to “Star and Planet Formation” for practical purposes.<br />
FOST is currently the largest of four teams at LAOG. It houses 20 staff members (including one on leave at<br />
CFHT), 3 post-docs, and 14 PhD stu<strong>de</strong>nts (in full or shared supervision). FOST evolves quickly. Since 2001,<br />
four permanent positions were allocated to our team: Gaspard Duchêne (CNAP), Nicolas Grosso (CNRS),<br />
Jean-Charles Augereau (CNAP), and Estelle Moraux (MdC-UJF). 5 post-docs visited us: David James (now<br />
a post-doc at Alabama State University), Tim Kendall (now assistant professor at University of Hertfordshire,<br />
UK), and Hi<strong>de</strong>ki Ozawa (now postdoc at Osaka University, Japan). Sylvia Alencar (Brazil) and Willem-Jan <strong>de</strong><br />
Wit (Holland) are the current FOST post-docs. At the time of writing, Claudio Zanni is about to join us in the<br />
framework of JETSET. 7 PhD dissertations were <strong>de</strong>fen<strong>de</strong>d successfully since 2001.<br />
The spectrum of FOST’s activities is broad. It spans the study of solar-like young stars and their environments<br />
(disks and jets) as well as the study of lower mass brown dwarfs and free-floating “planets” in nearby star<br />
forming regions. It also covers the study of the more evolved so-called “<strong>de</strong>bris disks” now found around stars<br />
of all masses, from A to M, and a census of the low-mass population of the Solar neighbourhood including, in<br />
particular, multiplicity and the search for extrasolar planets by radial velocity. All these efforts have a common<br />
long term goal: Our Origins, i<strong>de</strong>ntify and un<strong>de</strong>rstand the mechanisms by which stars and planets form and<br />
evolve.<br />
In the following sections, our main activities are <strong>de</strong>scribed. The presentation aims at highlighting not all,<br />
but some important results obtained by FOST members recently. Hopefully, the presentation will also clearly<br />
show that within FOST, the activities are now tightly the various intertwined and the boundaries between the<br />
former groups that merged to form FOST are vanishing quickly, both in terms of scientific goals and in terms<br />
of human resources. This is felt as a success by all of us. This feeling is further strengthened by the superb<br />
(and still growing) synergy between FOST and all other teams at LAOG: with SHERPAS for the star-disk<br />
interaction and jets physics; with ASTROMOL for the coupling of dust and gas studies in protoplanetary disks,<br />
and with GRIL for providing some of the key instruments to reach our science goals.<br />
6.2 Scientific Highlights<br />
• Direct images of planetary mass companions around 2 objects in young nearby associations (2MASSW J120733<br />
79
393254 (5MJup at 55 AU) & AB Pic (13-14 MJup at 250AU)). These results were obtained with the<br />
NACO/VLT Adaptive optics instrument, built in part at LAOG. (Chauvin et al. 2004, 2005a, 2005b.)<br />
• Dynamical masses: First astrometric mass <strong>de</strong>termination for a planet, around Gliese 876b: 1.89±0.34MJup<br />
(Benedict et al. 2002). Similarly, astrometric meaurements of stellar masses in binary systems. Accuracies<br />
on the mass of a few percents are reached on nearby L dwarf 2MASSW J0746425+2000321 (Bouy et al.<br />
2004) and ∼ 10% for young stars V773 Tau, DF Tau, and TWA 5 (Duchêne et al. 2003).<br />
• The Universality of the “present day” Mass Function observed down to at least 30 Mjup (the<br />
sensitivity limit of the surveys carried) in several young open clusters (e.g., Moraux, Bouvier, & Clarke<br />
2005). Improvements, i.e., completeness down to a few MJup, is expected soon after the commissioning<br />
of WIRCAM/CFHT, built partly at LAOG.<br />
• The very inner structure of young B star MWC 297 revealed by NIR interferometry. For the first<br />
time, the respective contributions from the disk and the wind are separated spatially & spectrally within<br />
the inner 1AU of the central source. These results were obtained with the interferometric near-infrared<br />
three- telescope recombiner AMBER/VLT, built in part at LAOG. (Malbet et al. 2005).<br />
The highlights listed above will also be found in the executive summary of the present document. It is<br />
significant that three of these four highlights from FOST were obtained with technology “ma<strong>de</strong> in LAOG”<br />
and also obtained by young members of FOST. This is a direct consequence of the good a<strong>de</strong>quation (the term<br />
synergy being probably more appropriate) between the science goals of FOST and the activities of the technical<br />
group. However, FOST being a large group, it is difficult, and ultimately unfair to many of its members, to<br />
limit the number of highlights to a short handful for a period of 4 years. Below are listed a few other interesting<br />
results.<br />
• Discovery of Earth-mass planets around Mu Arae (14 Earth masses, Santos et al. (2004)) and around<br />
the M dwarf Gliese 581 (17 Earth masses, Bonfils et al. (2005), in press).<br />
• Spatially resolved emission from Nanograins and PAH’s in disks of intermediate mass stars evi<strong>de</strong>nced<br />
by mid-IR spectroscopy and direct imaging. (Augereau et al. 2005, in prep.; Ménard, Pinte, &<br />
Duchêne, in collaboration with CEA/Saclay). The continuum thermal infrared imaging of T Tauri<br />
disks, seen in scattered light up to 12µm in this case, revealing the first clear observational signs of vertical<br />
dust settling. (McCabe et al. 2003).<br />
• Monitoring of X-ray variations in V1647 Ori (McNeil’s nebula) to study the star-disk interaction<br />
zone during an enhanced accretion phase: evi<strong>de</strong>nce for a powerful accretion shock on the photosphere of<br />
a low-mass star. (Grosso et al. (2005)).<br />
• The non-steady state of the accretion and ejection processes revealed at all timescales covered<br />
by our monitoring campaigns (from a few minutes to years). See Dougados et al. (2005) for a review.<br />
• Survey for Binaries in embed<strong>de</strong>d protostars to i<strong>de</strong>ntify the initial conditions for star formation /<br />
early stellar evolution immediately after fragmentation of the molecular core. (Duchêne et al. 2004).<br />
• Dynamical mo<strong>de</strong>ls of the circumbinary ring aroung GG Tau to explain the puzzling sharp outer edge.<br />
(Beust & Dutrey (2005a,b)), and of the very young <strong>de</strong>bris disks HD 141569 to search for traces of planets<br />
(Augereau & Papaloizou (2004)).<br />
• Discovery of several new brown dwarfs in the Taurus cloud, helping to show that the number<br />
fraction of brown dwarfs in this low <strong>de</strong>nsity star forming region is consistent with the ones in <strong>de</strong>nser<br />
regions like Orion.(Guieu et al., 2006, A&A 446, 485).<br />
6.3 Selected Topics in Star Formation and Early Stellar Evolution<br />
Accretion disks are key ingredients in the cocktail of events that lead from the collapse of a molecular cloud to<br />
the formation of a solar-like star. They are the entities by which the infalling material transits on its way to<br />
80
the central star. They regulate the distribution of angular momentum, provi<strong>de</strong> the material and the energy to<br />
launch jets, provi<strong>de</strong> the raw material to form planets, etc... Not surprisingly, a large fraction of our activities<br />
has been historically <strong>de</strong>voted to the search and study of these disks around young solar-like stars. With time<br />
however, our spectrum of activities has broa<strong>de</strong>ned. Today, it inclu<strong>de</strong>s the study of both to the inner parts of<br />
these disks and the study of the mass-loss phenomenon, itself strongly coupled to the accretion process, and<br />
possibly to the star-disk interaction zone. Disks around brown dwarfs and A stars are also consi<strong>de</strong>red now,<br />
further broa<strong>de</strong>ning our spectrum.<br />
To carry this research, LAOG proved to be a unique place. For example, to study the mass-loss process,<br />
strong ties with SHERPAS gave us access to coherent, cutting edge physical mo<strong>de</strong>ls of MHD disk winds able to<br />
predict jet rotation rates and emission-line ratios (Pesenti et al. 2004) (both now observed) while the presence of<br />
GRIL and the technical group gave us prime access, very early on, to the best available high angular resolution<br />
data obtained with adaptive optics and interferometry. In the sections below, we <strong>de</strong>scribe some of these results.<br />
6.3.1 Observation and mo<strong>de</strong>ls of young accretion disks<br />
The Outer dust disk<br />
Studies of the properties of T Tauri disks were initially based on the analysis of the spectral energy distribution<br />
(SED) only, for lack of available images (e.g., Beckwith et al. 1990, AJ, 99, 924). The first images of disks<br />
seen in scattered light became available in 1996 with HST in the optical and ground-based adaptive optics in<br />
the near-infrared (Burrows et al. 1996, ApJ, 473, 437 for HH 30 with HST; Roddier et al. 1996, ApJ, 463, 326<br />
for GG Tau with AO). Maps of disks at longer wavelengths became available roughly at the same time with<br />
millimeter interferometers (e.g., Dutrey et al. 1996, A&A, 309, 493).<br />
Today, SED fitting still provi<strong>de</strong>s useful constraint on the disk structure, (e.g., inner radius, flaring surface,<br />
vertical inner rim, ec) and to some extent on the dust properties (size distribution, opacity law) but the more<br />
difficult image fitting, coupled with SED fitting, is proving much more powerful.<br />
After being very active in searching for new disks in the previous 4-year period, but see Chauvin et al.<br />
(2002) for the recent discovery of the edge-on disk Lk Hα 263 C, our efforts are now going into improving the<br />
wavelength coverage of known disks, from scattered light images in the optical and near- to mid-infrared, e.g.,<br />
Stapelfeldt et al. (2003); Duchêne et al. (2004) to thermal emission maps in the millimeter range, e.g., (Duchêne<br />
et al. 2003). Our image fitting mo<strong>de</strong>ls, largely improved by Christophe Pinte (ongoing PhD thesis), is based<br />
on a powerful 3D Monte Carlo radiative transfer scheme. The analysis and publication of several datasets is<br />
currently un<strong>de</strong>rway.<br />
In the visible and near-infrared (shortwards of 2µm), we have used VLT and HST to gather additional<br />
images of several known disks. This effort involves long standing collaborations with Karl Stapelfeldt (JPL)<br />
and Andrea Ghez (UCLA).<br />
Simultaneous multi-wavelength image fitting is important because the scattering properties (i.e., albedo,<br />
phase function, polarisation) of dust grains <strong>de</strong>pend on wavelength and these mo<strong>de</strong>l offer a better probe of the<br />
grain size distribution and disk parameters than fitting a single image does.<br />
Comparing our previous HST image of the edge-on disk around HK Tau B (Stapelfeldt et al. 1998) to a<br />
2.2µm image of the system that we obtained with VLT’s NAOS (see Fig.6.1) shows that the dust grains in that<br />
disk are at least as forward-throwing in the near-infrared than they are in the visible (Ménard et al. 2006),<br />
clearly showing the presence of larger grains. This result is further supported by the <strong>de</strong>tection of scattered light<br />
at 12 microns (McCabe et al. 2003, see Fig.6.1).<br />
This result is extremely interesting as grains several microns in size are nee<strong>de</strong>d to produce significant scattering<br />
at 10µm. This encouraging results prompted us to obtain more observations in the mid-infrared (3–20 µm)<br />
on other disks, in particular during the first public observing campaign offered with the laser-gui<strong>de</strong>d adaptive<br />
optics systems on the Keck telescope and during commissioning of VISIR at the VLT. In all disks observed so<br />
far, we have revealed the presence of much larger dust grains than those found in the interstellar medium.<br />
In addition, in the GG Tau circumbinary ring, Duchêne et al. (2004) <strong>de</strong>monstrated that the scattered<br />
81
2.2 µ m<br />
0.5"<br />
11.7 µ m<br />
Figure 6.1: Left Panel: K-band image of the edge-on disk HK Tauri B ontained with NACO/VLT. (image<br />
from Ménard et al. (2005), in prep.). Right panel: 12µm scattered light image of HK Tau B obtained with<br />
KECK/LWS. Image from McCabe et al. (2003)<br />
light at 4µm comes from a layer located twice as close to the ring midplane than the visible scattered light<br />
(see Figure 6.2). Combined with the need for larger grains to account for the scattering phase function in the<br />
thermal infrared, and the need for very small grains at the disk surface to account for the large polarisation<br />
observed (Silber et al. 2000, ApJ, 536, L89), this is the first direct evi<strong>de</strong>nce for the stratification of dust grains,<br />
possibly as a result of vertical settling. This settling is a necessary step for dust to accumulate in the disk<br />
midplane and to grow into planetesimals, i.e., to start forming larger bodies, eventually rocky cores of planets,<br />
in the disks.<br />
0.8 µ m 3.8 µ m<br />
1"<br />
Figure 6.2: Left Panel: HST/ACS F814W image of the circumbinary ring of GG Tau (image from Krist et al.<br />
2005, ApJ, in press). Right panel: 3.8uµm scattered light image obtained with KECK. Image from Duchêne<br />
et al. (2004)<br />
To further probe small grains, and whenever possible, polarimetric mapping is also obtained. However, due<br />
to the paucity of polarimetric data, studies have been completed only for a few sources so far. Silber et al.<br />
(2000, ApJ, 536, L89) presented to first polarisation of a disk (GG Tau). Glauser et al. (2005) in prep. are<br />
finalising the analysis for IRAS 04158+2805. Our group is one of the very few using that powerful property of<br />
light for disk studies.<br />
In a parallel approach to scattered light images, we pursue millimeter interferometric images of T Tauri<br />
82<br />
E<br />
E<br />
N<br />
N
disks. At these wavelength, the bulk of the emission comes from the midplane of the outer disk, a region that is<br />
not probed by scattered light images which are sensitive to grains in the disk surface. By attempting to mo<strong>de</strong>l<br />
simultaneously the millimeter thermal emission and the scattered light images, we are constraining the vertical<br />
structure of disks and the possible presence of mm-sized particles in the disk midplane. In our first millimeter<br />
study of the edge-on disk around HK Tau B, based on data collected at IRAM’s Plateau <strong>de</strong> Bure Interferometer,<br />
we have shown that the disk must have layered structure, with a physical disconnection between the midplane<br />
and disk surface in or<strong>de</strong>r to explain all observations of that disk (Duchêne et al. 2003).<br />
To complement the various types of images <strong>de</strong>scrived above, we are also involved in the ”Core To Disk”<br />
Spitzer Legacy Survey, from which we hope to construct complete SEDs over the entire infrared range (from 3<br />
to 170µm). Combined with the constraints obtained from the analyses of the disk images, this will allow us to<br />
probe the parts of the disk that are not well sampled by current imaging techniques.<br />
Our efforts in the observation (and mo<strong>de</strong>ls) of protoplanetary disks are well received and lead to several<br />
invitations for review talks at international conferences, including a full review chapter awar<strong>de</strong>d (with Ménard<br />
PI) at the prestigious Protostar & Planets V conference (Hawaii, Oct.2005).<br />
To wrap-up this section, it is our hope that mo<strong>de</strong>ls of numerous protoplanetray disks will help us i<strong>de</strong>ntify<br />
systematic trends and characterise important physical mechanisms like setlling, or show the presence of asymmetries<br />
and complex dust properties, to un<strong>de</strong>rstand the processes by which disks evolve, a mid-term goal, and<br />
ultimately form planets, a long term-goal.<br />
The inner dust disk<br />
While the section above <strong>de</strong>alt mostly with the outer parts of disks, say 30AU and outwards, i.e., the resolution<br />
available with HST and ground based adaptive optics at 150pc, the distance of nearby star forming regions,<br />
other members of team FOST focus their attention on the inner disk by using another high angular resolution<br />
technique, namely infrared interferometry. The goal of these efforts is to investigate the physical conditions in<br />
the disk close to central star and to better un<strong>de</strong>rstand the different evolution stages of these disks.<br />
To reach these goals, data is obtained from most existing interferometers (PTI, IOTA, VINCI, MIDI). We<br />
have also improved our interpretation capacities by <strong>de</strong>veloping a co<strong>de</strong> <strong>de</strong>aling with the vertical structure of disks<br />
and other radiative transfer tools based lambda iteration and Monte Carlo techniques to extract predictions<br />
from the vertical structure co<strong>de</strong>.<br />
Finally, a part of the team is involved, through GRIL, in the <strong>de</strong>velopment of new instruments like IONIC<br />
on IOTA and AMBER on the VLTI. Thanks to this instrumental involvement, we have access to a large part<br />
of observing time at IOTA and part of the AMBER guaranteed time but also a privileged access to the VLTI<br />
Science Demonstration Time on objects not observable by the existing instruments.<br />
The staff involved over the period 2001-2005 inclu<strong>de</strong> Jean-Philippe Berger, Fabien Malbet, Jean-Louis Monin,<br />
together with PhD stu<strong>de</strong>nts Regis Lachaume, Carla Gil, Eric Tatulli, and Myriam Benisty and un<strong>de</strong>rgraduate<br />
stu<strong>de</strong>nts F. Millour (Master 2 stu<strong>de</strong>nt) and E. Herwats (Master 2 stu<strong>de</strong>nt).<br />
Mo<strong>de</strong>ls of vertical structure To analyse the interferometric observations our mo<strong>de</strong>ls of the vertical structure<br />
of disks have been improved following the initial work by Malbet & Bertout, 1991, ApJ, 383, 814), as part of<br />
the PhD thesis work of R. Lachaume. Influenced by the approach of Chiang & Goldreich (1997, ApJ, 490, 368),<br />
Lachaume <strong>de</strong>velopped a two layer mo<strong>de</strong>l that provi<strong>de</strong>s an a<strong>de</strong>quate analytical solution to the more complex<br />
numerical simulations (Lachaume et al. 2003). This mo<strong>de</strong>l successfully reproduces the observations of T Tauri<br />
disks: both the SED and the visibilities. It also predicts that in the inner zone where the viscous dissipation<br />
is the main heating source, the flaring angle of the disk surface is driven by the accretion and the opacity<br />
contrarily to the outer disks where it is driven by the direct stellar radition heating. Lachaume et al. (2003)<br />
further showed that at the same radius, the outgoing flux can be dominated by the stellar flux reprocessing<br />
whereas the vertical structure of the central layers are regulated by the accretion rate, see Fig. 6.3.<br />
FU Orionis un<strong>de</strong>r scrutiny Malbet & Berger conducted the largest interferometric campaign to date on<br />
the young stellar object FU Orionis, as part of an international collaboration including observations on PTI,<br />
83
Figure 6.3: Contribution of heating processes in a T Tauri disk: radial profile of these contributions to the temperature<br />
of the disk. Left: mid-plane temperature, middle: effective temperature, right: surface temperature.<br />
One sees that in the inner 2 AUs the mid-plane temperature is dominated by the viscous dissipation. From<br />
Lachaume et al. (2003).<br />
IOTA and VLTI/VINCI.<br />
Figure 6.4: FU Orionis disk-spot mo<strong>de</strong>l. Lines corresponds to the best mo<strong>de</strong>l fit and markers to visibilities in<br />
binned form. Top-left panel: spectral energy distribution and best fit mo<strong>de</strong>l. The solid line stands for the whole<br />
mo<strong>de</strong>l and the dashed one for the spot. Right panel: visibility data vs. hour angle for each baseline in H and<br />
K. The contribution of the disk is displayed in dashed lines. Bottom-left panel: synthetic image in logarithmic<br />
scale. East is left and North is up. From Malbet et al. (2005).<br />
FU Ori was observed on 42 nights over a period of 6 years, from 1998 to 2003. 287 in<strong>de</strong>pen<strong>de</strong>nt measurements<br />
of the fringe visibility with 6 different baselines ranging from 20 to 110m, in the H- and K-bands, were obtained,<br />
see Fig. 6.4. Our data resolve FU Ori at the AU scale, and provi<strong>de</strong>s new constraints at shorter baselines and<br />
shorter wavelengths. Our extensive (u,v)-plane coverage, coupled with the published spectral energy distribution<br />
data shows that FU Ori hosts an active accretion disk whose temperature law is consistent with standard<br />
mo<strong>de</strong>ls. A 10% peak-to-peak oscillation is <strong>de</strong>tected in the longest baseline data. It is interpreted as a possible<br />
disk hot-spot or companion. Although this bright spot on the surface of the disk could be tracing some thermal<br />
instabilities in the disk, we have proposed to interpret this spot as the signature of a companion of the central FU<br />
Ori system on an extremely eccentric orbit. We speculate that the close encounter of this putative companion<br />
and the central star could be the explanation of the initial photometric rise of the luminosity of this object.<br />
84
Wind and disk interaction in MWC 297 The young stellar object MWC 297 is an embed<strong>de</strong>d B1.5Ve<br />
star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has<br />
been observed by the AMBER/VLTI instrument on a 45m baseline in a region of the K spectral band centered<br />
around the Brγ line. The object has been resolved in the continuum with a visibility of 0.50 +0.08<br />
−0.10 in the Brγ<br />
line, where the flux is about twice larger than in the continuum, with a visibility about twice smaller 0.33±0.06.<br />
We applied a combined mo<strong>de</strong>l that inclu<strong>de</strong>s a geometrically thin accretion disk mo<strong>de</strong>l consisting of gas and<br />
dust and a stellar wind mo<strong>de</strong>l. The hydrogen emission, about twice more resolved than the continuum, can be<br />
reproduced by the emission of a latitu<strong>de</strong>-<strong>de</strong>pen<strong>de</strong>nt wind mo<strong>de</strong>l above the disk surface. A picture is emerging<br />
in which MWC 297 is surroun<strong>de</strong>d by an equatorial flat disk, possibly still accreting, and an outflowing wind<br />
which has a much higher velocity in the polar region than at the equator (Malbet et al. 2005, A&A, submitted).<br />
These observations are the first to separate spatially and spectrally the disk radiation and the wind emission<br />
within the inner 1 AU from the central sources. It shows the power of AMBER and many similar sources will<br />
be observed and yield hopefully to a better un<strong>de</strong>rstanding of the connection between the disk and the wind in<br />
young stellar objects.<br />
6.3.2 The star-disk interaction<br />
The previous section <strong>de</strong>alt with the parts of the disk located typically at a few AU’s from the star (1-3 AU).<br />
Moving further inward, the dust in the disk sublimates and only gas is left. At one point the disk material<br />
moving inward because of accretion will encounter the top of the stellar magnetosphere. Whether the accretion<br />
flow will keep going “equatorially” to form a boundary layer before reaching the photosphere or be channelled<br />
by the magnetic field <strong>de</strong>pends on the relative balance between “magnetic pressure” and “accretion pressure”.<br />
Magnetospheric accretion, i.e. the magnetic channelling of the accretion flow from the inner disk onto the<br />
star, is now believed to be a central process in young stars in that it regulates their angular momentum during<br />
pre-main sequence evolution, diverts part of the accretion flow into a powerful ionized jet, and possibly halts the<br />
inward migration of proto-Jupiters close to the young star. FOST’s involvement in the study of magnetospheric<br />
accretion is mostly observational. However, to improve our capacity for mo<strong>de</strong>ls and interpretations, a PhD<br />
thesis (N.Bessolaz) has been started jointly with SHERPAS in november 2004.<br />
Magnetospheric accretion<br />
Our work aims at <strong>de</strong>riving the structure of the magnetospheric cavity, the physical conditions at the inner disk<br />
edge and in magnetic funnel flows (accretion columns), as well as constraining the temporal evolution of the<br />
whole structure. With this goal in mind, we have organised and performed several international campaigns of<br />
observations involving between 10-15 observatories world-wi<strong>de</strong> and an even larger number of collaborators. By<br />
monitoring the spectroscopic, photometric and polarimetric variability of young stars on a timescale of several<br />
weeks, we characterize the dynamical processes (accretion, ejection, magnetic field evolution) involved in the<br />
magnetospheric accretion process (Bouvier et al. 1999, A&A, 439, 619; Bouvier et al. 2003; Ménard et al.<br />
2003).<br />
We thus showed that the observed variations of the photometric and spectral diagnostics (luminosity, line<br />
profiles an intensity, veiling, etc.) were broadly consistent with the magnetospheric accretion concept : all<br />
diagnostics are modulated on a timescale of a week which reflects the rotation of the star and its magnetosphere<br />
up to the inner disk edge. Hence, all accretion signatures (hot spot at the stellar surface, veiling, accretion<br />
columns) vary in phase as the whole magnetospheric accretion structure rotate at the same angular velocity<br />
than the star. The photospheric luminosity is modulated as well, with the same period but anti-phased. This<br />
suggests that the inner disk edge is warped by the stellar magnetosphere as material is lifted up above the<br />
disk plane to be loa<strong>de</strong>d into magnetic funnel flows and thus periodically occults the central star. This further<br />
indicate that the stellar magnetosphere is inclined relative to the stellar rotational (and disk) axis (Bouvier et<br />
al. 2003).<br />
While the observed variability can be broadly accounted for in the framework of the magnetospheric accretion<br />
mo<strong>de</strong>l, we additionally showed that the variability pattern changes over a timescale of several weeks. This<br />
indicates that the magnetospheric structure itself reacts to the interaction with the disk perhaps in a cyclic-like<br />
fashion, first inflating as the result of differential rotation between the star and the disk, then opening and<br />
reconnecting to eventually return to its initial, roughly dipolar configuration. We have reported evi<strong>de</strong>nce for<br />
85
such mid-term (several weeks) magnetospheric cycles from the observed modulation of both accretion and wind<br />
diagnostics in long time series of observations (Bouvier et al. 2003).<br />
These results first confirm the validity of the magnetospheric accretion paradigm but also prompt new<br />
<strong>de</strong>velopments in the analytical and numerical mo<strong>de</strong>ls. As observations suggest, the magnetically-mediated<br />
accretion process is highly non-axisymmetric and quite time-<strong>de</strong>pen<strong>de</strong>nt as a result of the feedback of accretion<br />
flow onto the magnetospheric structure. These refinements are now just being inclu<strong>de</strong>d into the latest numerical<br />
simulations of magnetospheric accretion in young stars (e.g., Romanova et al. 2004, ApJ, 610, 920). These results<br />
have been acknowledged in the community and prompted invitations to give reviews at several international<br />
conferences, the most recent one being a full review chapter awar<strong>de</strong>d on this subject (with Bouvier PI) at the<br />
Protostar & Planets V conference (Hawaii, Oct.2005).<br />
This work, led by our group at LAOG (Bouvier, Dougados), has been ma<strong>de</strong> possible through a large number<br />
of collaborations, sometimes fun<strong>de</strong>d by official programs (e.g. MAE 2003-2004, Econet 2005-2006), and multiple<br />
visits of collaborators (from 2 weeks up to 1 yr; CNRS, MENRT): K. Grankin and M. Ibrahimov, Uzbekistan;<br />
S. Alencar and J. Vasconcelos, Brazil; J. Muzerolle, USA; C. Clarke, UK.<br />
With a number of stringent observational constraints now at hand, we have embarked into the <strong>de</strong>velopment<br />
of more realistic MHD mo<strong>de</strong>ls to <strong>de</strong>scribe the magnetospheric accretion/ejection process in young stars. Within<br />
a collaborative framework involving both FOST (Bouvier) and SHERPAS (Ferrreira) at LAOG, as well as an<br />
expert MHD group at University Utrecht (Keppens) a joint thesis has been started (N. Bessolaz) in September<br />
2004 on the <strong>de</strong>velopment of 2D numerical simulations of magnetically-channelled flows. A broa<strong>de</strong>r perspective<br />
is also offered by the start of the FP6 RTN JETSET (2005-2008) of which LAOG is a no<strong>de</strong> (Dougados PI) and<br />
which inclu<strong>de</strong>s the investigation of the magnetospheric accretion process as a possible source of jet outflows.<br />
Finally, we will now attempt the first direct <strong>de</strong>tection of the magnetospheric cavity in young stars through<br />
interferometric measurements with VLTI/AMBER in GTO programs (Dougados, Bouvier, Malbet).<br />
X-rays to probe the star-disk interaction during accretion outbursts<br />
The typical accretion rates in T Tauri stars (10 −7,−8 M⊙/yr) is too weak for accretion pressure to rule over<br />
magnetospheric pressure, forcing the infalling material to proceed along the field lines, i.e., magnetospheric<br />
accretion (see previous section). For higher accretion rates however, the inner rim of the disk moves closer to<br />
the photosphere, possibly reaching the photosphere for extreme accretion rates. A boundary layer results.<br />
Young solar-like stars are thought to experience these phases of extreme accretion (10 −4,−5 M⊙/yr) several<br />
times during their early life. During these accretion bursts, known as FU Orionis and EX Lupi phases, the<br />
luminosity of the object is dominated by the emission of the heated inner disk. In that case, direct study of the<br />
star-disk interaction zone is next to impossible by “classical” methods.<br />
In November 2003, the “anonymous” star V1647 Ori erupted dramatically and produced the rise of the<br />
McNeil’s nebula, discovered serendipitously by amateur astronomer McNeil in Jan. 2004. This outburst is<br />
explained by an increase of the disk accretion rate from 6 × 10 −7 to 10 −5 M⊙ yr −1 . N.Grosso from FOST, in<br />
collaboration with J.Kastner (Rochester Institute of Technology) used Chandra (an american X-ray satellite<br />
observatory) to reveal a factor ∼100 increase in the X-ray flux of this source compared to pre-outburst values.<br />
The coinci<strong>de</strong>nce of this surge in X-ray brightness with the optical/infrared outburst <strong>de</strong>monstrates that strongly<br />
enhanced high energy emission occurs as a consequence of high accretion rates in V1647 Ori (Kastner et al.<br />
2004).<br />
Follow-up observations with XMM-Newton confirmed the high levels of X-ray emission observed with Chandra,<br />
and showed enhanced X-ray variability from V1647 Ori in outburst (Grosso et al. 2005). The observed<br />
variability of the X-ray flux does not appear typical of X-ray flares from other young stellar objects, and could<br />
be produced by the Keplerian rotation of a warped accretion disk. A follow-up project at IRAM has been<br />
started by Grosso in collaboration with team ASTROMOL to characterise the accretion disk of V1647 Ori.<br />
86
6.3.3 The physics and origins of mass-loss in T Tauri stars<br />
The physical mechanism by which mass is ejected from accreting systems and collimated into jets is another<br />
fundamental problem in star formation that FOST is interested in. MHD accretion-driven wind mo<strong>de</strong>ls appear<br />
required to explain the efficient collimation and the large ejection to accretion ratio of 0.01-0.1. Two broad<br />
classes of mo<strong>de</strong>ls have been proposed: ejection from the stellar surface, or magnetocentrifugal ejection from<br />
the associated accretion disk. Distinguishing between these scenarii is vital not only for un<strong>de</strong>rstanding the jet<br />
phenomenon in itself, but also for mo<strong>de</strong>lling the formation of exoplanets, as they have distinct implications on<br />
the <strong>de</strong>nsity structure and the migration processes in the inner regions of protoplanetary disks.<br />
At the T Tauri phase (at ages > 10 6 yrs), most of the residual infalling envelope is evacuated, allowing direct<br />
observation of the inner 100 AUs where ejection mo<strong>de</strong>ls predict that most of the collimation and acceleration<br />
processes occur. Since 1996, C.Dougados and co-workers have been conducting sub-arcsecond observations of<br />
the central regions (a few 100 AUs) of the jets associated with T Tauri stars. These observations are confronted<br />
to <strong>de</strong>tailed predictions from MHD wind mo<strong>de</strong>ls to constrain the jet launching mechanism in these sources.<br />
This work is done in close collaboration with S. Cabrit (LERMA, Obs. <strong>de</strong> Paris), J. Ferreira (LAOG) and<br />
P. Garcia (University of Porto). A thesis work on this subject was conducted by N.Pesenti (LAOG). These<br />
observational constraints have so far favored a disk wind origin: the increase of jet widths with distance, the<br />
onion-like structure of the DG Tau jet with faster gas nested insi<strong>de</strong> slower material, and the <strong>de</strong>tection of<br />
rotation signatures are all successfully reproduced by MHD wind mo<strong>de</strong>ls with launch radii of 0.1-3 AU. Our<br />
main contributions in the past 4 years are <strong>de</strong>tailed below.<br />
One of the major breakthroughs, in recent years, has been the report of tentative rotation signatures in 4<br />
T Tauri microjets (Bacciotti et al. 2000, ApJ, 537, L49; Woitas et al. 2002, ApJ, 580, 336; Coffey et al. 2004,<br />
Ap&SS, 292, 553). It has been soon recognized that the measure of azimuthal velocities is a powerful tool to<br />
constrain the streamline launching radius (Bacciotti et al. 2002, ApJ, 576, 222). Azimuthal velocities directly<br />
computed from observed velocity shifts indicate launching radii in the range 0.1-3 AU, the strongest indication<br />
to date of a disc wind origin. In his thesis work, Nicolas Pesenti, has shown however that projection and dilution<br />
effects significantly alter the <strong>de</strong>rivation of azimuthal velocities from observed velocity shifts and that a careful<br />
and <strong>de</strong>tailed comparison with mo<strong>de</strong>l predictions is required (Pesenti et al. 2003). Extending the analytical<br />
work of An<strong>de</strong>rson et al. (2003), we have also computed predicted azimuthal velocities in the context of X- and<br />
stellar-winds (Ferreira et al. submitted).<br />
In or<strong>de</strong>r to fully test the reported rotation <strong>de</strong>tections in T Tauri jets, we have also launched an observational<br />
campaign with the IRAM Plateau <strong>de</strong> Bure interferometer to map rotation in the associated disk. So far disk<br />
rotation has been checked against jet rotation for only 2 sources and the results are perplexing. While the<br />
DG Tau circumstellar disk appears to rotate in the same direction as reported for the jet (Testi et al. 2002,<br />
A&A, 394, L31), the RW Aur disk does not! (Cabrit et al. A&A submitted). These observations further suggest<br />
that care should be taken in the interpretation of reported T Tauri jet rotation signatures. Further jet sources<br />
will be observed at IRAM/PdBI in the forthcoming years within the JETSET/RTN collaboration.<br />
Exploring jet tracers in the near-infrared domain is critical to analyse current AO observations obtained on<br />
8m-class telescopes and efficiently prepare future observations with AMBER/VLTI (The LAOG is co-I on 2<br />
GTO AMBER/VLTI observations on T Tauri jet sources). Another aspect of Pesenti’s thesis work was therefore<br />
to <strong>de</strong>velop a tool for the prediction of the near-infrared [Fe ii] line emission of wind mo<strong>de</strong>ls. This tool was first<br />
applied to the self-similar disk wind mo<strong>de</strong>ls <strong>de</strong>velopped by Ferreira and collaborators from SHERPAS (Pesenti<br />
et al. 2003).<br />
6.3.4 Observations and mo<strong>de</strong>ls of the more evolved “Debris disks”<br />
Debris disks are circumstellar dust disks imaged in scattered light around young main sequence stars (typically<br />
10 Myr or ol<strong>de</strong>r). Contrary to genuine protoplanetary disks, these environments contain almost no gas and are<br />
optically thin. Their dynamics is therefore mostly gravitational. These disks are interesting because they are<br />
probably young planetary systems that are not fully dynamically relaxed. Their study is then of great interest<br />
for our un<strong>de</strong>rstanding of the processes that give birth and make evolve planetary systems in general.<br />
The prototype of these disks is the dust disk orbiting the star Beta Pictoris which remained, for many years,<br />
the only one known. In the past 5 years, our group has been involved in the discovery of new <strong>de</strong>bris disk<br />
87
systems: HD 141569, HD 32297, HD 181327. Other disks like HR 4796 and AU Mic for example were also<br />
studied by our group. (Augereau et al. 1999, A&A, 348, 557; Boccaletti et al. 2003).<br />
Since <strong>de</strong>bris disks are optically thin, their dust <strong>de</strong>nsity profiles can be directly extracted from spatially<br />
resolved scattered light images. When available, the colors of the disk (in scattered light) can be related directly<br />
to the size distribution of the smallest dust grains (Boccaletti et al. 2003; Augereau et al. 2004). The situation<br />
is slightly more complex for edge-on disks (Beta Pic, AU Mic, HD32297 for instance) and a specific inversion<br />
procedure was <strong>de</strong>veloped in or<strong>de</strong>r to reconstruct the dust <strong>de</strong>nsity from brightness profiles (e.g., Augereau &<br />
Beust, A&A, submitted for AU Mic). These profiles, once inclu<strong>de</strong>d into the <strong>de</strong>bris disk radiative tranfert mo<strong>de</strong>l<br />
we <strong>de</strong>velopped to adjust the SED, give insight on the dust properties (grain size distribution, composition).<br />
The mo<strong>de</strong>l results serve as inputs for our dynamical mo<strong>de</strong>ling of the colliding planetesimals disks that release<br />
the observed dust grains (e.g., Augereau et al. 2001). They are also incorporated into the chemistry mo<strong>de</strong>l of<br />
the remnant gas disk around HD 141569 that we have <strong>de</strong>tected with the IRAM Interferometer (Augereau et al.<br />
in prep.).<br />
Although the inner regions of most <strong>de</strong>bris disks appear to be largely dust-<strong>de</strong>pleted, the actual amount of<br />
dust is poorly known. Our group is involved in the <strong>de</strong>tection and mo<strong>de</strong>ling of a very small amount of dust<br />
in the Vega inner system (within about 1AU) based on CHARA/FLUOR infrared interferometric observations<br />
(Absil et al., submitted). This exo-zodiacal dust population around Vega may be related to collisions among<br />
asteroid-like objects and/or due to evaporating comets.<br />
Beta Pictoris itself has been studied now for years by our group. In the past 4 years, a collaboration has<br />
been initiated with members of the <strong>Laboratoire</strong> <strong>de</strong> Planétologie <strong>de</strong> <strong>Grenoble</strong> (LPG). The goal was to better<br />
un<strong>de</strong>rstand the physics of planetesimal evaporation in the vicinity of the star. In<strong>de</strong>ed, repeated transient changes<br />
in the absorption spectrum of Beta Pictoris had been attributed for years to the sublimation of star-grazing<br />
planetesimals. The goal of the collaboration was to translate mo<strong>de</strong>ls of solar system comets to the case of Beta<br />
Pictoris to better un<strong>de</strong>rstand the physics of their sublimation and better constrain the mo<strong>de</strong>l. This constituted<br />
the thesis of C.Karmann un<strong>de</strong>r the supervision of H.Beust. The main outcome of the study was that the<br />
planetesimals in the Beta Pic system contain probably very little ice, and that their sublimation rate <strong>de</strong>pends<br />
on their distance to the star but also on their history, with possible seasonal effects (Karmann et al., 2001;<br />
2003).<br />
6.3.5 Dynamical evolution of young circumstellar environments<br />
Our team has also <strong>de</strong>velopped a long-term collaboration with the group of John Papaloizou (QMWC and Cambridge,<br />
UK) to mo<strong>de</strong>l the complex structures of spatially resolved <strong>de</strong>bris disks. The mo<strong>de</strong>ls involve pertubing<br />
planets like in the Beta Pic and Vega disks (Augereau et al. 2001; Reche et al., in prep.) but also the effect<br />
of radiation and wind drag forces on the grains (e.g., AU Mic, Augereau & Beust, submitted). In the case of<br />
Beta Pic, this type of approach has allowed to place an upper limit on the gas mass in the system (Thébault &<br />
Augereau, 2005). Some systems like HR 4796 are not isolated and the effect of stellar companions must be investigated.<br />
In the case of HD 141569 for instance, we show that the large-scaled spiral structure observed likely<br />
results from the secular perturbation of the disk by the two bound M-star companions (Augereau & Papaloizou<br />
2004, see Fig. 6.5). As part of the PhD thesis of R.Reche, we are now exploring the effects of an additional<br />
perturber, a Jupiter-mass planet, on the inner disk structure that remains unexplained.<br />
The grains observed in <strong>de</strong>bris disks arise from mutual collisions between larger particles (up to km-sized<br />
bodies). We have thus started to numerically investigate the outcome of collisions in <strong>de</strong>bris disks to predict the<br />
size distribution as a function of time and distance from the star to see if it could affect the interpretation of<br />
the observations, especially the mid-infrared excesses measured with ISO and Spitzer.<br />
6.3.6 Other Topics in Star Formation<br />
X-ray emission from Young Stellar Objects<br />
Many members FOST are involved in several long exposure observations of star forming region called ‘large<br />
projects’, a highly competitive category of Chandra and XMM-Newton observations. This effort is lead by<br />
88
Figure 6.5: Observation and mo<strong>de</strong>l of the spiral structure in the disk of HD 141569. Left Panel: HST/ACS<br />
optical observations. The image is <strong>de</strong>-projected to provi<strong>de</strong> a pole-on view of the disk.Middle Panel: Synthetic<br />
image of disk showing the spiral structure caused by the remote companions. Right Panel: Geometry of the<br />
multiple system.<br />
N. Grosso who participates actively in all programmes, together with T.Montmerle (Astromol). Other members<br />
of FOST are actively involved in XEST (Bouvier, Dougados, Ménard, Monin, and PhD stu<strong>de</strong>nt Guieu). The<br />
surveys we participate in are:<br />
• The Chandra Orion Ultra<strong>de</strong>ep Project (COUP) COUP is a nearly continuous observation of the Orion<br />
nebula cluster over about 13. days that took place in Jan. 2003. It yiel<strong>de</strong>d an exceptionally <strong>de</strong>ep total onsource<br />
exposure time of about 10 days. A total 13 papers, with 8 co-signed by N.Grosso and T.Montmerle<br />
(ASTROMOL), were published in the October 2005 COUP special issue of The Astrophysical Journal<br />
Supplement.<br />
• The X-ray Emission Survey of the Taurus Molecular Cloud (XEST) This X-ray survey of the Taurus<br />
Molecular Cloud with XMM-Newton was proposed by Manuel Gü<strong>de</strong>l (Paul-Scherrer Institut, Zürich). It<br />
is closely linked to the Taurus optical survey carried by our group at CFHT, and with a Spitzer survey<br />
(PI is D.Padgett, Caltech) of the same zone. Data is currently being analysed for all three surveys.<br />
• The Deep Rho Oph XMM-Newton Observation (DROXO) The <strong>de</strong>nse core F of the ρ Ophiuchi dark cloud<br />
was first studied in X-Rays by H.Ozawa (postdoc from April 2002 to March 2004) with an exposure of<br />
33 ks with XMM-Newton. Ozawa et al. (2005) <strong>de</strong>tected 87 X-ray sources, of whom 25 are new X-ray<br />
sources. DROXO, proposed by Salvatore Sciortino (Palermo observatory), is a ten day long XMM-Newton<br />
observation of roughly the same area to study spectral and variability properties of young stellars objects.<br />
Observations have been performed on March 2005.<br />
Spitzer Legacy surveys: Cores-to-Disks (C2D)<br />
Our team is involved in the Spitzer c2d Legacy program <strong>de</strong>signed to study the evolution of circumstellar matter<br />
’From Molecular Cores to Planet-Forming Disks”. This program utilizes in particular the improved sensitivity<br />
of the Spitzer InfraRed Spectrograph (IRS5, 5-35 micron) to study ices towards low-mass embed<strong>de</strong>d protostars<br />
(Boogert et al., 2004) and toward extincted background stars. The Spitzer/c2d spectra toward a variety of<br />
solar-type PMS stars also greatly expand the study of infrared emission features in solar-mass stars, which<br />
previously were restricted primarily to ground-based studies in the 10 micron window. A large fraction of the<br />
silicates features are weak and flat, consistent with micron-sized grains indicating fast grain growth. In addition,<br />
approximately half of the T Tauri star spectra show crystalline silicate features near 28 and 33microns indicating<br />
significant processing when compared to interstellar grains (Kessler-Silacci, Augereau et al., submitted).<br />
Furthermore, PAH emission is observed towards at least 5 T Tauri stars out of 33, with 11 tentative <strong>de</strong>tections<br />
still to be confirmed, resulting in a lower limit of 15% <strong>de</strong>tection of PAH in T Tauri stars (Geers, Augereau et al.,<br />
in prep). Although PAH features are wi<strong>de</strong>ly observed, in particular in circumstellar disks around Herbig stars,<br />
there was no consensus before these results on the presence of PAHs in protoplanetary disks around T Tauri<br />
stars and whether or not they were receiving sufficient stellar radiation to produce observable signatures.<br />
89
C2D Spitzer/IRAC and MIPS data of star forming regions, coupled with our optical surveys of the same<br />
clouds, are used to study the presence and properties of disks around brown dwarfs and weak-line T Tauri stars.<br />
6.4 Selected topics on the IMF and the properties of low-mass Populations<br />
6.4.1 The low-mass population of nearby Star Forming Regions<br />
The brown dwarf population of the Taurus Molecular cloud<br />
In 2000, we initiated a <strong>de</strong>ep large scale optical survey of the Taurus molecular cloud at CFHT. Today, the<br />
coverage of the cloud is of or<strong>de</strong>r of 30% and we have unveiled 17 new brown dwarfs in this low <strong>de</strong>nsity star<br />
forming region (Guieu et al. 2005, and PhD Thesis). Taking into account the 4 brown dwarfs also discovered<br />
by our group earlier, Martin et al. 2001, we have ∼doubled the number of known substellar objects in this<br />
star forming region. We have studied the spatial distribution of the brown dwarfs in Taurus, and contrarily to<br />
previous claims, we find that there is no brown dwarf <strong>de</strong>ficit in Taurus. The ratio of brown dwarfs to stars in<br />
Taurus is now consistent with other estimations elsewhere, in Orion for example.<br />
We also find that a significant number of brown dwarfs show Hα emission and other signatures of accretion,<br />
indicative of the presence of circumstellar disks. Using our collaboration with the Spitzer C2D legacy team, we<br />
are currently investigating the mid-infrared excess of numerous brown dwarfs in Taurus. These results show<br />
that half of the brown dwarfs in Taurus harbor a significant infrared excess, hence possess a circumstellar disk.<br />
Figure 6.6: Spatial distribution of newly found BD in Taurus (open triangles) and previously known BD (open<br />
circles). Black dots locate Taurus young stars. Image credit: S.Guieu.<br />
90
Multiplicity of protostars<br />
Following our investigation of multiple systems among low-mass PMS and ZAMS stars aimed at constraining<br />
the star formation process from the statistics of multiplicity (e.g., Duchêne, 1999, A&A, 341, 547), we have<br />
recently focussed on the earliest stages of star formation by investigating the multiplicity of near-infrared<br />
embed<strong>de</strong>d sources in star forming regions. These embed<strong>de</strong>d sources are the observable objects closest to the<br />
protostellar stage. Duchêne & Bouvier, with Co-I André & Motte (Saclay), and Bontemps (Bor<strong>de</strong>aux) <strong>de</strong>rived<br />
the fraction of wi<strong>de</strong> binaries among these sources from direct near-IR imaging at CFHT and ESO. An excess of<br />
multiple systems compared to ol<strong>de</strong>r low-mass stars in the field is found. This new result, for the youngest stellar<br />
objects known, tends to confirm the ubiquity of fragmentation during molecular core collapse, thus leading to<br />
multiple protostars which later <strong>de</strong>cay through dynamical relaxation or are disrupted by gravitational encounters<br />
in <strong>de</strong>nse clusters (Duchêne et al. 2004).<br />
Taking advantage of the unique capabilities of the near-infrared wavefront sensor of the NACO Adaptative<br />
Optics system on VLT, we are now in the process of investigating the tightest of these protostellar systems,<br />
down to a resolution of 10 AU. Preliminary results reveal a number of close systems with separations in this<br />
range, see Fig. 6.7. A complete census of multiple protostellar systems over the range 10-1500 AU awaits the<br />
completion of the VLT NACO runs. Meanwhile, we have started follow up spectroscopy of the faintest and<br />
most embed<strong>de</strong>d companions to protostars, with the aim to search for proto-brown dwarfs. In 2005,we will also<br />
obtain the first VLTI-MIDI mid-infrared interferometric observations of these objects, in an attempt to <strong>de</strong>tect<br />
the tightest embed<strong>de</strong>d multiple systems, thereby setting constraints on the fragmentation scenario for systems<br />
just a few AU appart, and to <strong>de</strong>termine the structure of the dusty envelopes surrounding these protostars.<br />
L1689 IRS 5 (ophiuchus) SVS 20 (Serpens) WL 20 (Ophiuchus)<br />
0.5"<br />
Figure 6.7: Three examples of multiple protostellar systems observed with VLT/NACO. Note the strange<br />
physionomy of the third companion of the WL 20 system, which is not an artefact but most likely an edge-on<br />
disk. Image credit G. Duchêne and J.Bouvier<br />
While our current results indicate a high frequency of multiplicity among protostars in<strong>de</strong>ed, thus supporting<br />
fragmentation during core collapse, we find no evi<strong>de</strong>nce for the existence of small-N unstable aggregates (N=5-<br />
10) in the protostellar stage, contrary to what several numerical mo<strong>de</strong>ls of core collapse predict through multiple<br />
fragmentation. This disagreement probably points to the simplified physics inclu<strong>de</strong>d so far in the numerical<br />
mo<strong>de</strong>ls which, for instance, neglect magnetic field, use a poorly constrained equation of state, and do not take<br />
into account feedback effects resulting from the strong wind of young protostars onto the collapsing cloud. Our<br />
results regarding the end products of core collapse in several star forming regions thus provi<strong>de</strong> some guidance<br />
to improve numerical mo<strong>de</strong>ls.<br />
On the nature of Infrared companions to T Tauri stars<br />
Taking advantage of the high-angular resolution imaging and spectroscopic <strong>de</strong>vices available on the VLT and<br />
Keck telescopes, we have been studying for the last few years the nature of the so-called ”infrared companions”<br />
to T Tauri stars. These objects are best exemplified by T Tau Sa, the optically un<strong>de</strong>tectable companion to the<br />
prototype young stellar object T Tau. The spectral energy distribution of these objects would classify them<br />
as embed<strong>de</strong>d, Class I protostars, but their close vicinity (a few tens to hundreds of AU) to more evolved T<br />
Tauri stars suggests otherwise. Using the Keck telescope in collaboration with Andrea Ghez (UCLA), we have<br />
obtained medium resolution near-infrared spectra of two such objects (T Tau Sa and V773 Tau D (Duchêne<br />
91<br />
E<br />
N
et al. 2002; 2003). We have found that their spectrum is entirely featureless, showing that they are either<br />
intermediate-mass early-type stars seen in scattered light due to heavy obscuration along our line-of-sight by<br />
some dusty circumstellar material or lower mass objects entirely embed<strong>de</strong>d in an optically thick envelope.<br />
In the case of T Tau Sa, we have further obtained a high resolution (R∼30000) near-infrared spectrum that<br />
clearly shows the presence of warm (∼400K) gaseous material on the line-of-sight to the central target; the<br />
absence of kinematical signatures of infall or outflow clearly suggests that the object is an early-type star that<br />
is surroun<strong>de</strong>d by a compact, opaque edge-on disk that has not been spatially resolved so far. More recently,<br />
VLT-NACO observations of another infrared companion system, WL 20 in Rho Ophiuchus (see Fig. 6.7, right<br />
panel), has revealed a complex nebulosity that is most likely seen in scattered light, again suggesting that<br />
the interpretation of these infrared companions in terms of embed<strong>de</strong>d protostars is unlikely to be an a<strong>de</strong>quate<br />
framework.<br />
In the near future, we plan on obtaining additional high angular resolution images in the near- and midinfrared<br />
of these systems, as well as high spectral resolution spectra in or<strong>de</strong>r to i<strong>de</strong>ntify photospheric features<br />
and/or gaseous material located along our line of sight to these objects.<br />
Binary stars and dynamical masses<br />
The mass of a star is probably its most fundamental property. It is however extremely difficult to measure<br />
directly and one usually relies on mo<strong>de</strong>ls (or mass-luminosity relations) to get an estimation. Of concern for<br />
us, pre-main sequence evolutionary mo<strong>de</strong>ls are subject to significant uncertainties related to the complexity of<br />
the various relevant physical processes. It is therefore necessary to <strong>de</strong>termine mo<strong>de</strong>l-in<strong>de</strong>pen<strong>de</strong>nt masses for T<br />
Tauri stars in or<strong>de</strong>r to calibrate the theoretical evolutionary tracks, in particular towards the low-mass end, as<br />
masses for very low-mass stars and brown dwarfs are then used in other studies, such as that of the initial mass<br />
function in star-forming regions.<br />
Using speckle interferometric observations of young tight binary systems at Keck in collaboration with<br />
Andrea Ghez (UCLA), we have monitored several tight T Tauri binary systems in or<strong>de</strong>r to <strong>de</strong>termine the<br />
orbital parameters and, eventually, the masses of these objects. Dynamical masses for several systems were<br />
obtained (V773 Tau (Duchêne et al. 2003); DF Tau, TWA 5) with typical accuracies of 10-20%, where the<br />
uncertainty in the distance to the system dominates the uncertainties in the Keplerian orbital fit. We have also<br />
applied the same technique to the orbit of a field star-brown dwarf system, 2MASS0746425+2000321 (Bouy et<br />
al. 2004), for which an accuracy of 5% was reached, this time helping to calibrate the relations valid for the<br />
lower-main sequence.<br />
As part of the AMBER consortium, we have obtained Guaranteed Observation Time to conduct the same<br />
type of project on much tighter (
masses up to 10 solar masses for a number of clusters and found that the mass distribution over this range can<br />
be <strong>de</strong>scribed by a single lognormal functional form. Second, we showed that the cluster’s MF is invariant, i.e.,<br />
the same for all the regions we studied, which suggest that the mass distribution of stars and brown dwarfs does<br />
not <strong>de</strong>pend much on environmental conditions at the epoch of formation. These results are now reasonably<br />
accounted for by new mo<strong>de</strong>ls of star (and brown dwarf) formation which rely on the fragmentation of molecular<br />
clouds resulting from MHD supersonic turbulence.<br />
Star formation mo<strong>de</strong>ls also predict a minimum mass for fragmentation of or<strong>de</strong>r of 3-8 Jupiter masses. Hence,<br />
the Initial Mass Function (IMF) is expected to have a lower limit at this scale. While the sensitivity of the<br />
optical surveys we have performed so far reached about 30 Jupiter masses, the advent of infrared mosaic cameras<br />
will now allow us to <strong>de</strong>tect brown dwarfs in young clusters down to a few Jupiter masses. We have therefore<br />
submitted a new large program at CFHT using WIRCAM, built in part at LAOG, in or<strong>de</strong>r to probe the low<br />
mass end of the mass function of young clusters, in the range from a few to 30 Jupiter masses. If granted,<br />
the surveys will start in 2006 and last for several semesters, thus completing our current results obtained from<br />
optical surveys (CFHT 12K, MEGACAM) and providing new clues to the formation and dynamical evolution<br />
of free-floating planetary mass objects in young clusters.<br />
As most of the collaborators involved in the optical surveys over the last few years will also participate to<br />
the new IR surveys (Cambridge, Arcetri, Potsdam, Cardiff, Kiel, Madrid, Canarias, Caltech, CFHT), we very<br />
recently applied for another FP6 RTN which will focus, at least in part, on the investigation of the extremes<br />
(upper and lower ends) of the IMF.<br />
In parallel, we have embarked in the mo<strong>de</strong>lling of the dynamical evolution of the lowest mass populations of<br />
star forming regions and young open clusters. Preliminary results obtained from numerical simulations using Nbody<br />
co<strong>de</strong>s (Moraux & Clarke 2005; Kroupa et al. 2003) suggest that the various competing scenarios of brown<br />
dwarf formation (collapse, ejection, etc.) may yield distinct cinematical signatures at young ages. Additional<br />
numerical simulations using the most recent N-body co<strong>de</strong>s (in collaboration with Aarseth, Cambridge) will<br />
refine the predicted dynamical evolution of young brown dwarfs in clusters, which we shall then be able to<br />
confront to the results of our CFHT large program.<br />
6.4.3 The low-mass population of the solar neighbourhood<br />
The multiplicity of M dwarfs<br />
With the goals of measuring very accurate dynamical masses and estimating the multiplicity fraction of the very<br />
low mass stars, we carried large programmes on nearby M-dwarfs. These programmes are nee<strong>de</strong>d to constrain<br />
star formation theories (multiplicity) and stellar physics (evolutionary tracks, mass-luminosity relations). By<br />
doing so, we uncovered more than 20 new companions (Beuzit et al. 2003; Forveille et al. 2004; 2005).<br />
Multiplicity properties are fairly well known for solar type stars (Duquennoy & Mayor 1991, A&A, 248,<br />
485; Halbwachs et al. 2003, A&A, 397, 159), but it is not the case for the lower main sequence. To date no<br />
<strong>de</strong>termination of the orbital element distribution for M-dwarf binaries has been published. However, multiplicity<br />
fractions ranging from 25% (Leinert et al. 1997, A&A, 325, 159) to 42% (Fischer & Marcy 1992, ApJ, 396, 178)<br />
have been announced.<br />
Our combination of radial velocity and adaptive optics imaging on M dwarfs is the most complete survey<br />
to date for stellar companions in the solar neighbourhood. Our results (Marchal et al. 2003; Marchal et al.<br />
2005 in prep) combined with those of Hinz et al. (2002, AJ, 123, 2027) for very wi<strong>de</strong> binaries enabled us to<br />
<strong>de</strong>rive the multiplicity of M dwarfs. The main results are: (1) a stellar multiplicity rate of 26 ± 3%; (2) M- and<br />
G-dwarfs have very similar separation distributions for separations un<strong>de</strong>r 10 a.u. (see Fig. 6.8), (3) at wi<strong>de</strong>r<br />
separations M dwarfs have a large companion <strong>de</strong>ficit relative to G dwarfs (see Fig. 6.8), (4) for both M- and<br />
G-dwarfs, the mass ratio distribution is a function of period, (5) similarly to G dwarfs, brown dwarfs are very<br />
rare within ∼100 a.u. of M dwarfs (the “so-called” brown dwarf <strong>de</strong>sert).<br />
These results favor a scenario where the G and M dwarfs form with i<strong>de</strong>ntical multiplicity properties. The<br />
<strong>de</strong>ficit of M dwarfs at large separations being due to preferential breakup of the looser sytems via dynamical<br />
interactions and orbital <strong>de</strong>cay in compact cluster (Sterzik & Durisen 1998, A&A, 339, 95). The contrasting mass<br />
ratio distributions at small and large orbital separations suggest that two distinct formation mo<strong>de</strong>s operate,<br />
93
Figure 6.8: Distribution of separations for multiple M-dwarfs of the Solar neighbourhood, compared with the<br />
distribution of solar-type multiples.<br />
one that produces a flat mass ratio distribution over a broad period range, and a second that only forms short<br />
period binaries with nearly equal masses.<br />
The multiplicity of L dwarfs<br />
Where do free-floating brown dwarfs come from? Are they ejected stellar embryos (Reipurth & Clarke 2001, AJ,<br />
122, 432), or do they form like “isolated” stars, by fragmentation of molecular cores? Searching for companions<br />
around L dwarfs is the logical next step to get a complete view of multiplicity accross the mass spectrum and<br />
answer these questions.<br />
To search for companions to L dwarfs, a part of the DENIS sample of ultracool dwarfs (Delfosse et al. 2003)<br />
was observed with HST/WFPC2 (Bouy et al. 2003). 15 new ultracool binaries are reported and statistical<br />
elements <strong>de</strong>termined. The observed frequency of ultracool binaries is lower than that of binaries with G-type<br />
primaries in the separation range from 0.42 AU to 80 AU. There is also a clear <strong>de</strong>ficit of ultracool binaries<br />
with separations wi<strong>de</strong>r than 15 AU and a ten<strong>de</strong>ncy for the ultracool binaries to have mass ratios near unity.<br />
Noteworthy, this astrometric work lead to the first <strong>de</strong>termination of the orbit and dynamical masses of a binary<br />
brown dwarfs: the L dwarf 2MASSW J0746425+2000321 (Bouy et al. 2004), mentioned before in this report.<br />
The <strong>de</strong>ficit of wi<strong>de</strong> ultracool dwarfs binaries reported above by Bouy et al. (2003), but also in Close et al.<br />
(2003, ApJ, 598, 1265) and Gizis et al. (2003, AJ, 125, 3302), is frequently presented as an argument in favour<br />
of the embryo-ejection scenario for the formation of brown dwarfs. To test this scenario, we obtained infrared<br />
images of a very large sample of ultracool dwarfs (250 DENIS late-M and L dwarfs) to <strong>de</strong>tect companion at<br />
separation larger than 1arcsec. We <strong>de</strong>tected the first wi<strong>de</strong> binary for this range of mass (Billères et al. 2005,<br />
see Fig. 6.9), which is clearly not formed by the embryo-ejection scenario. One consequence of this discovery is<br />
that, although rare, low-mass pairs exist and brown dwarfs do not form solely by embryo ejection.<br />
Surveys for field brown dwarfs<br />
For the last 10 years we have used the DENIS survey to find very-late M- and L-dwarfs in the solar neighbourhood<br />
(see for example Crifo et al. 2005; Kendall et al. 2004; Phan-Bao et al. 2003; and Delfosse et al. 2003 for<br />
94
Figure 6.9: Top panels: DENIS discovery images of D0551 in I- and J-band. In J-band the object is well<br />
visible with a magnitu<strong>de</strong> J=15.3. Bottom Panels: SOFI images, with better resolution, revealing the binarity<br />
of D0551.<br />
the latest results). A large sample of 300 very late M- and L-dwarfs, i<strong>de</strong>ntified over 5700 square <strong>de</strong>grees(!) of<br />
DENIS data, resulted. The sample is complete for objects red<strong>de</strong>r than I-J=3.0 (M8) and brighter than I=18,<br />
and thus statistically well <strong>de</strong>fined. It is an excellent basis for studies of the Galactic disk population of very<br />
low mass stars and brown dwarfs, allowing clean <strong>de</strong>terminations of the luminosity function, mass function, and<br />
multiplicity fraction.<br />
Recently, we exten<strong>de</strong>d our study by including the CFHT-Legacy Survey data, with three main goals in mind:<br />
find ultracool brown dwarfs (T
with only three known to date. Most mass <strong>de</strong>terminations for Very Low Mass Stars (VLMS) are therefore instead<br />
obtained from visual and interferometric pairs, which until recently, have not yiel<strong>de</strong>d comparable precisions on<br />
mass estimates. By combining very accurate radial velocities with precise angular separations from adaptive<br />
optics, our team reached accuracies of only 1-3% for VLMS (Forveille et al. 1999; Delfosse et al. 1999b;<br />
Ségransan et al. 2000; 2003). To date, masses were <strong>de</strong>termined for ∼30 M dwarfs with accuracies ranging<br />
between 0.5 and 5% by us, with additional measurements becoming available as the time span of our surveys<br />
catches up with longer period systems.<br />
As predicted by stellar structure mo<strong>de</strong>ls, the metallicity dispersion of the field population induces a large<br />
scatter around the mean V-band relation, while the infrared relations are much tighter.<br />
Figure 6.10: V-band Mass-Metalllicity-Luminosity relation. The red filled circles represent our metallicity<br />
<strong>de</strong>terminations and the blue open circles those from WW05. The symbol size is proportional to the metallicity,<br />
and the dashed contours represent iso-metallicity for our calibration, spaced by 0.25 <strong>de</strong>x from +0.25 (left) to<br />
-1.75 <strong>de</strong>x (right). The solid lines are the V-band empirical M/L relation of Delfosse et al. 2000.<br />
In Delfosse et al. (2000) it was suggested that metallicity might explain most of this intrinsic dispersion<br />
on the visible mass-luminosity relation, but for lack of quantitative metallicity estimates we could not pursue<br />
this suggestion further. Recently (Bonfils et al. 2005, in press) <strong>de</strong>termined the metallicities for 20 M-dwarfs in<br />
wi<strong>de</strong>-binary systems that also contain an F-, G- or K-star, un<strong>de</strong>r the simple assumption that the two stars have<br />
the same composition. We used this data to <strong>de</strong>rive a photometric calibration of the metallicities of very lowmass<br />
stars. The calibration is valid between 0.8 and 0.1 M⊙, needs V- and K-band photometry and an accurate<br />
parallax, and provi<strong>de</strong>s metallicity estimates with ∼0.2 <strong>de</strong>x uncertainties. We use these new metallicity estimates<br />
to take a fresh look at the V-band mass-luminosity relation, and <strong>de</strong>monstrate that its intrinsic dispersion is<br />
in<strong>de</strong>ed due to metallicity. The first mass-metallicity-luminosity relation for M dwarfs is hence <strong>de</strong>termined (see<br />
Fig. 6.10).<br />
6.5 Selected topics on Extra-Solar Planets<br />
About 150 planetary system have to date been unveiled around stars other than our Sun. They were initially<br />
searched for, and found, around solar-type stars (e.g., Mayor & Queloz 1995, Nature 378, 355; Marcy G.W. &<br />
Butler R.P., ARAA, 36, 57). As a result of this bias, only a few planets around stars with very different masses<br />
are known.<br />
One major motivation to look for planets around “non solar-like stars” is to constrain the planet formation<br />
96
process by comparing its outcome for solar-type stars and for stars of much lower (or larger) mass than the<br />
Sun. Are planetary systems as frequent or not? Do their orbital and mass distributions differ? The answer to<br />
these questions is at present totally unknown.<br />
Surveys for planets around very low mass stars and massive stars are difficult because very low mass stars<br />
are faint, making the measurement of accurate radial velocities expensive in telescope. On the other hand,<br />
massive stars combine high rotational velocities and a small number of photospheric lines, making accurate<br />
spectroscopy a challenge.<br />
In our group, because of the long time collaborations we have been maintaining with the Geneva observatory,<br />
in particular with its exoplanet group, we have been involved early on in radial velocity surveys for planets<br />
around solar-type stars. This was a natural follow-up to the astrometry programmes that had been going-on<br />
for solar-type and low mass stars (led in particular by C.Perrier). This section of our activities is not <strong>de</strong>scribed<br />
in <strong>de</strong>tails here. Instead, we focus on the more challenging planet hunts around low-mass and high mass stars.<br />
6.5.1 Search for planets around very low mass stars<br />
In 2003 members of FOST integrated the HARPS consortium with the duty to pilot the search for planets<br />
around M-dwarfs (Delfosse is PI). 10% of the Harps Guaranteed Time goes to this program (10 nights/yr<br />
during 5 years). The accuracy of the radial velocities reached by HARPS on very low mass stars is between 1 to<br />
3 m.s −1 and semi-amplitu<strong>de</strong>s of 10 m.s −1 are <strong>de</strong>tectable easily. They correspond to planets of 6 Earth masses<br />
in 3-day orbits around a 0.15M⊙ star (13 Earth masses for a 0.6 M⊙ star), or 40 Earth mass planets for a 1000d<br />
period around a 0.15M⊙ stars (100 Earth mass around a 0.6 M⊙ star).<br />
Bonfils et al. (2005b) reported the discovery of a Neptune-mass planet around Gl 581 (M3V). The planet<br />
has a circular orbit of P = 5.366 days (see Fig. 6.11). The minimum mass of the planet (m2 sin i) is only<br />
0.052 MJup = 0.97 MNep = 16.6 MEarth making Gl 581b one of the lightest extra-solar planet known to date.<br />
The Gl 581 planetary system is only the third centered on an M dwarf, joining the Gl 876 three-planet system<br />
(Delfosse et al. 1998, A&A, 338, L67) and the lone planet around Gl 436 (Butler et al. 2004, ApJ, 617, 580).<br />
Its discovery reinforces the emerging ten<strong>de</strong>ncy for such planets to be of low mass, and found at short orbital<br />
periods.<br />
Figure 6.11: Upper panel: Phased radial velocities for Gl 581. Lower panel: Residuals around the fitted solution<br />
versus time. The weighted RMS of the residuals around the fit is only 2.5 m s −1 . ¿From Bonfils et al. (2005).<br />
In 2006 we plan to start a large program of radial velocity measurements with SOPHIE, the new spectrograph<br />
of the OHP-1.93m telescope. An accuracy of ∼ 3m.s −1 is expected. With both programs, our sample will reach<br />
97
300 objects, a size sufficient for statistical studies.<br />
Notwithstanding the caveats raised in the beginning of this section regarding the cost of measuring accurate<br />
radial velocity for faint M-dwarfs, this type of stars remains extremely interesting for future planet search<br />
programmes, in particular when potent imagers will come on-line, like ESO’s Planet Fin<strong>de</strong>r. In<strong>de</strong>ed, M dwarfs<br />
are by far the most abundant objects in the Solar neighbourhood, with 100 of the 120 nearest stars being<br />
M dwarfs. Their proximity makes them very favourable targets for astrometric searches. Similarly, planetary<br />
system around M dwarfs are i<strong>de</strong>al targets for astrometric measurement of the reflex motion: the very low mass<br />
of the star results in a more favourable mass ratio, and, again, the (statistically) smaller distance produces a<br />
larger angular motion for a given linear displacement. We very recently obtained the first astrometric mass<br />
<strong>de</strong>termination of a planet (Benedict, McArthur, Forveille, Delfosse et al. 2002) around Gl 876. Needless to say,<br />
the planets discovered by the present program will be i<strong>de</strong>al targets for the PRIMA instrument of the VLTI, if<br />
a suitable reference can be found, as well as for the space astrometry missions. Finally, the brightness contrast<br />
between an M-star and a Jupiter-like planet is very favourable in the infrared for a planet imaging campaign<br />
like the one envisaged with ESO’s PLANET FINDER instrument.<br />
6.5.2 Search for planets around F- and A-stars<br />
The massive Main Sequence stars (spectral type earlier than F8V) have not been investigated for planets until<br />
recently because exhibit a low number of stellar lines (typically a few dozens to a few hundreds for A-F type<br />
stars versus a few thousands for Solar-type stars), and these lines are generally broa<strong>de</strong>ned by high rotational<br />
velocities (typically 20-200 km/s versus a few km/s). However, knowing about the presence of planets or brown<br />
dwarfs around more massive objects is also of importance. We already know that the disks around these massive<br />
stars and Solar-type stars are different in terms of properties at similar ages: in<strong>de</strong>ed T Tauri disks aged a few<br />
Myrs appear to be less evolved than those around massive stars aged also a few Myrs such as HD 141569 or<br />
HR 4796, which tend to show that these disks, as the parent stars, evolve more rapidly (Lagrange and Augereau,<br />
2004). The occurence and time scale of planet formation have to be investigated and compared similarly.<br />
Figure 6.12: ELODIE radial velocity data and orbital solutions for a F6V star showing periodic radial velocity<br />
variations corresponding to the presence of a 9.1 MJup planet orbiting at 1.1 AU (period of 388 days). The<br />
eccentricity is 0.34. Top: Radial velocities. Bottom: Residuals to the fitted orbital solution.<br />
The way to process the data and extract the information on radial velocity variations on lower mass stars is<br />
not straightforwardly applicable to more massive stars (Griffin et al, 2000, A&A Suppl. Ser., 147, 299-321). We<br />
introduced (Chelli, 2000, A&A, 358, L59) a new radial velocity measurement method, consisting in correlating,<br />
for a given star and in the Fourier space, each spectrum and a reference spectrum built by summing up all the<br />
spectra, which are specific of the consi<strong>de</strong>red star.<br />
98
With this new tool at hands, searches for low mass companions around A-F type stars are performed since<br />
2003, in a collaboration between the LAOG and Geneva Observatory teams: radial velocity observations are<br />
obtained with ELODIE (Northern hemisphere) and HARPS (Southern hemisphere). Studies based on such<br />
observations lead to the conclusion that this new RV measurement method can be applied to A-F type stars in<br />
the frame of planet/BD searches (Galland et al., 2005a, A&A, submitted): with ELODIE, the planetary domain<br />
can be reached for A type Main-Sequence stars with v sin i up to 100 km/s and orbital periods less than 10<br />
days. For late A type stars, the accessible range is v sin i up to 80 km/s and orbital periods up to 100 days.<br />
Planetary masses can be <strong>de</strong>tected for all F type Main-Sequence stars. With HARPS, RV uncertainties are lower<br />
(by a factor of 5 to 7), and the planetary domain is accessible for all A and F type stars, even with large v sin i.<br />
100 stars have now been observed with ELODIE at least twice, and 65 at least four times, leading to the<br />
<strong>de</strong>tection of RV variations in 17 cases. Seven of them have a probable planetary origin. A first planet, around<br />
an F6V star has already been characterized (Galland et al., 2005b, A&A, submitted), see Fig. 6.12.<br />
Complementary adaptive optics imaging observations of the same sample has been started with PUE’O at<br />
CFHT (Northern hemisphere), in or<strong>de</strong>r to search for companions with large periods, and to test the correlation<br />
between binarity and the presence and properties of planets found by radial velocity.<br />
In 2006, we plan to increase (up to 300 objects) the size of our A-F Main Sequence stars sample for radial<br />
velocity observations with SOPHIE. The sample of stars observed with HARPS will also be increased to 300<br />
objects.<br />
6.5.3 Low-mass companions and planets in nearby associations<br />
The field of extrasolar planet <strong>de</strong>tection and characterization has been limited, so far, to the domain of indirect<br />
<strong>de</strong>tection measurements, either by radial velocity or photometric transit surveys. However, this exploration is<br />
presently intrinsically limited to the close circumstellar environment, typically within ∼4 AU of the central star.<br />
With the <strong>de</strong>velopment of high contrast and high angular resolution instrumentation, the situation is changing<br />
and the exploration of planets with large semi-major axes becomes achievable.<br />
Figure 6.13: Offset positions in terms of separation (Top) and position angle (Bottom) of 2M1207 b from A,<br />
on 27 April 2004, 5 February 2005 and 31 March 2005 (full circles with uncertainties). The expected variation<br />
of offset positions, if b is a background object, is shown (solid line), based on a distance of 70 pc, a proper<br />
motion of (µα, µδ) = (−78, −24) mas yr-1 for A and the initial offset position of b from A. Also reported are the<br />
associated uncertainties (sha<strong>de</strong>d region) and the different contributions (distance, proper motion, initial offset<br />
position) in dotted lines.<br />
Young and nearby open clusters are i<strong>de</strong>al targets for such programmes since lower mass objects such as<br />
brown dwarfs and giant planets are brighter when they are young and can thus be more easily <strong>de</strong>tected. It is<br />
99
therefore no surprise that vast efforts were ma<strong>de</strong> to discover new nearby associations in recent years. Today,<br />
seven nearby associations, open clusters, or so-called ”groups” are known, that are closer than 100 pc from the<br />
Sun with ages of ∼ 10 Myr, or less. We have conducted adaptive optics surveys of several of these associations<br />
in the past 5 years, using the ADONIS, PUEO and NAOS adaptive optics systems.<br />
Figure 6.14: K-band coronagraphic image of AB Pic A and b obtained on 17 March 2003. The diameter of the<br />
occulting mask is 1.4”.<br />
In the course of this on-going <strong>de</strong>ep imaging survey of young, nearby southern associations (Chauvin et<br />
al. 2003), we used the ESO VLT telescope and its adaptive optics near-infrared instrument NACO to image<br />
the close vicinity of the source 2MASSWJ 1207334-393254 (hereafter 2M1207). This brown dwarf 2M1207<br />
was i<strong>de</strong>ntified by Gizis (2002, ApJ, 575, 484) as a member of the young (8 Myr) TW Hydrae Association<br />
(TWA), a result corroborated later by measurements at optical, infrared, and X-ray wavelengths. In the close<br />
circumstellar environment of 2M1207 A, we discovered a faint planetary mass companion candidate in April<br />
2004 (Chauvin et al. 2004), at ∼780 mas (55 AU). See the discovery image on the cover page of the current<br />
(FOST) chapter. Subsequent observations of 2M1207 A and b, obtained in August 2004 by Schnei<strong>de</strong>r et al.<br />
(2004, A&AS, 205, 1114) using the Hubble Space Telescope (HST) and on February and March 2005 with<br />
NACO by our team, clearly <strong>de</strong>monstrate that the two objects are comoving (Fig. 6.13). They enable us to<br />
reasonably confirm the status of a planetary mass companion to the brown dwarf 2M1207 A. Photometry and<br />
spectroscopy are consistent with a spectral type L5-L9.5 for the companion. Based on H, K and L’ photometry<br />
and evolutionary mo<strong>de</strong>ls, for an age of 8 +4<br />
−3 Myr, we found 2M1207b to lie within the planetary regime, i.e., a<br />
mass of M = 5 ± 2 MJup and an effective temperature of Teff = 1250 ± 200K.<br />
As part of the same <strong>de</strong>ep imaging survey of young nearby associations, we also obtained a direct image<br />
(Fig. 6.14) of a 13—14 MJup companion, assuming an age of ∼30 Myr, at 250 AU of the star AB Pic, a member<br />
of the large Tucana-Horologium association (Chauvin et al. 2005).<br />
These <strong>de</strong>tections provi<strong>de</strong> the first images of planetary mass companions in systems other than our own. It<br />
is very unlikely that these giant planets formed within a circumstellar disk, but more probably via one of two<br />
formation mechanisms proposed for brown dwarfs. These discoveries offer proofs that such mechanisms can<br />
form bodies down to the planetary masses and open new perspectives for our un<strong>de</strong>rstanding of chemical and<br />
physical properties of planetary mass objects as well as their formtion mechanisms.<br />
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Chapter 7<br />
Future Research Directions<br />
7.1 Research Plans<br />
Over the last few years, since the creation of FOST in 2003, we have progressively refocussed our activities<br />
by including the unifying long-term goal of ”planet formation” to our present goal of un<strong>de</strong>rstanding ”star<br />
formation”. Recall that the acronym FOST stands for ”Star and Planet Formation” in its contracted form.<br />
Because such a re-orientation takes time and must be smooth to maintain a good coherence within a larger<br />
team, not everyone in FOST works directly on ”planet formation” today. We are convinced this is the right<br />
way because we foresee that our broad range of expertise will lead to innovative breakthroughs in the long run,<br />
breakthroughs that would otherwise have been missed.<br />
In<strong>de</strong>ed, because of the richness of the scientific background in FOST, we are consi<strong>de</strong>ring the problem from a<br />
number of in<strong>de</strong>pen<strong>de</strong>nt and interesting directions: be it from the direct search for planets around main sequence<br />
stars and in younger star forming regions, be it the study of proto-planetary disks where planets are thought<br />
to form, or be it the impact of mass-loss on the disk structure, possibly changing the conditions for planet<br />
formation and migration, for example.<br />
This shift in perspective for FOST is rather new. As a consequence, our work should largely keep going<br />
in the current directions for the next few years, i.e., largely into the 2007-2010 period we are consi<strong>de</strong>ring<br />
here. Therefore, a large fraction of our forecasted activities has been <strong>de</strong>scribed in the previous chapter. It is<br />
nevertheless useful to recall a few directions we are engaged in and to raise a few questions that will, undoubtedly,<br />
drive our research in the longer term.<br />
In the field of Star Formation We plan to take advantage of JETSET (starting fall 2005) to make advances<br />
in the 2D and 3D numerical simulations of the magnetically mediated star-disk interaction zone (in relation<br />
with SHERPAS). The goal is to confront realistic mo<strong>de</strong>ls with our observations. On the observational si<strong>de</strong>, our<br />
involvement in programmes using 2 powerful spectropolarimeters, ESPADONS at CFHT and NARVAL at TBL<br />
(soon), should allow us to obtain the first, and long awaited for, maps of the magnetic field in this zone. Today<br />
this field is assumed dipolar, but just how close to reality is this hypothesis? The use of X-rays to probe that<br />
zone is original and we will benefit also from the rare expertise we have in this field.<br />
Clearly, the scientific exploitation of AMBER, NACO, and WIRCAM is also at the center of our activities.<br />
The expected returns from these new instruments has been <strong>de</strong>scribed before, but WIRCAM should allow us<br />
to i<strong>de</strong>ntify planet-mass objects in nearby star forming regions and estimate the shape of the IMF down to a<br />
few Jupiter masses only, a key piece of information to constrain the star formation mechanisms. NAOS and<br />
AMBER will be extensively used to map disk, from their inner parts (AMBER) to signatures of large scale<br />
asymmetries (NACO), possibly tracing planets. The interpretation of these observations will require continued<br />
efforts to improve our disk mo<strong>de</strong>ls and radiative transfer tools. The need for dynamical mo<strong>de</strong>ls is expected to<br />
increase with time, together with the quality of data available from these instruments.<br />
A long term target for these studies is the preparation for Herschel and ALMA that will provi<strong>de</strong> the necessary<br />
101
data to verify the predictions we are making today regarding the structure and evolution of protoplanetary disks<br />
(e.g., dust settling, grain growth, planetesimal formation). PLANET FINDER and VITRUV will complete these<br />
data sets and mo<strong>de</strong>ls by providing images with unprece<strong>de</strong>nted resolution and contrast.<br />
One aspect of our activities that will be new is the study of mineralogy in disks. With instruments like NACO,<br />
VISIR, and SPITZER, we expect to improve our knowledge of the dust properties in disks (size, composition).<br />
This is nee<strong>de</strong>d to remove the usual assumption that grains are ISM-like and spherical in disks...<br />
In the field of IMF and low-mass stars we will push further our studies of the substellar populations<br />
by looking for planet-mass objects with large surveys like UKIDSS and the WIRCAM Key project we have<br />
proposed. In the Galactic field, the CFHT-LS will be exploited (and completed by programmes led by FOST<br />
members) to look for the coolest objects, the T-dwarfs and the ammonia-dwarfs (or Y-dwarfs).<br />
In parallel with statistical studies, we consi<strong>de</strong>r it important to start studying the individual properties<br />
of these poorly known objects. Masses, metallicities, effective temperatures, etc., will be gathered. Their<br />
atmospheres will be probed by polarimetry (already started, e.g., Ménard et al. 2002) and spectroscopy. We<br />
do no have the expertise yet for the interpretation of planetary atmospheres. Filling that gap is a priority.<br />
In the field of Extra-Solar planets the search for extremely low-mass companions will continue and their<br />
characterisation will ramp up in our work load. With the current instrumentation, these companions offer pretty<br />
much our only chance to <strong>de</strong>tect direct photons from a planet-mass object external to our Solar system. Much<br />
has to be learnt.<br />
HARPS on the ESO 3.60m and soon SOPHIE at OHP will also improve our sample of planets around M<br />
and A dwarfs to a point where statistical studies and follow-ups will become possible. We expect to play a<br />
leading role in both aspects. Both programmes are very recent. They were <strong>de</strong>scribed in our activity report and<br />
will be carried on for most of the period covered by the present research plan.<br />
To characterise the exo-planets, interferometry will play a large role in our future programmes. It will be<br />
used to <strong>de</strong>rive astrometric masses for numerous objects (with PRIMA for example).<br />
7.2 Needs in personnel<br />
The range of expertise within FOST is broad. New results, often at the very forefront of competitive fields,<br />
are obtained regularly by FOST and progress is being ma<strong>de</strong> rapidly. It is therefore difficult, at the present<br />
time, to know exactly what our needs will be terms of personnel in the years to come. Still, a few “profiles”<br />
are emerging, involving specific expertise, that would fulfill forecasted needs in FOST. But by no means should<br />
these few “profiles” be consi<strong>de</strong>red <strong>de</strong>finitive or restrictive. Actually, there is much to bet that new needs will<br />
emerge as we make progress, as is normal in science.<br />
It is easy to imagine that very specific competences to <strong>de</strong>al with continuum radiative transfer (for Herschel<br />
& ALMA) coupled with PLANET FINDER and VITRUV might become nee<strong>de</strong>d. Similarly, the latter two<br />
instruments might trigger the need for a data reduction specialist in high contrast, high resolution imaging to<br />
favor full scientific return. On the other hand, <strong>de</strong>aling with extremely large databases (like those involved in<br />
our current surveys) also requires very specific competences that might become critical a few years down the<br />
road. So clearly, new needs will emerge that we cannot predict today.<br />
Nevertheless, a few profiles can be i<strong>de</strong>ntified today that would fulfill needs within FOST. They should be<br />
seen as a starting point for our list of requirements in personnel.<br />
• Detection of exoplanets and statistical properties (urgent: 2007-2008)<br />
The French planet hunters have access to the best instruments to measure radial velocities (e.g., SOPHIE<br />
& HARPS). These efficient spectrographs allow to study large samples. Statistical properties can be<br />
<strong>de</strong>rived and planet formation theories tested. LAOG is leading the search for planets around M- and<br />
A-dwarfs in Europe. The analysis work is done as part of two PhD thesis currently un<strong>de</strong>r way in FOST<br />
102
at LAOG (in collaboration with Geneva Obs.). This chapter of our activities is un<strong>de</strong>rstaffed and there is<br />
a pressing need for manpower to maintain our position in the current consortia.<br />
• Radiative transfer in emission lines, interpretation of spectroscopic data (mid-term: 2008-2009)<br />
To follow-up on broad-band continuum observations of disks, on low-resolution spectral classification spectra<br />
of brown dwarfs, or to estimate the physical conditions in ionised atomic jets and accretion columns,<br />
FOST is becoming more and more involved in low, mid- and high spectral resolution observations. However,<br />
no one currently at LAOG as the expertise to <strong>de</strong>al with radiative transfer in lines. It is important to<br />
fill that void in FOST if we are to push further our un<strong>de</strong>rstanding of the mechanisms linking accretion and<br />
ejection, and more specifically to elucidate the links between the inner disk and the mass-loss phenomenon<br />
where data is becoming available rapidly with AMBER.<br />
• Dynamical mo<strong>de</strong>ls of (proto-)planetary disks (mid-term:2008-2009)<br />
Today, LAOG has access to powerful (symplectic) co<strong>de</strong>s able to calculate the dynamics of dust disks, without<br />
gas, or follow the gas disk, but without dust. The advances permitted by such co<strong>de</strong>s are tremendous,<br />
but it is absolutely clear that disks around young stars are ma<strong>de</strong> of gas and dust and both are important:<br />
gas controls the dynamics, dust controls the temperature equilibrium, roughly speaking. In or<strong>de</strong>r to look<br />
for traces of planets, to un<strong>de</strong>rstand the dynamics of disks, and ultimately their evolution, FOST needs<br />
to <strong>de</strong>velop new numerical tools able to <strong>de</strong>al simultaneously with the gas and dust components of disks.<br />
These co<strong>de</strong>s must be fast and stable to follow the evolution over a long time span. Furthermore, these<br />
co<strong>de</strong>s must be coupled to radiative transfer tools in or<strong>de</strong>r to compare with the observations. This is an<br />
extremely complex problem but tentative solutions have been imagined and an international collaboration<br />
has been started to <strong>de</strong>velop such new tools. FOST, currently leading the programme, is un<strong>de</strong>rstaffed<br />
(because of teaching load) to <strong>de</strong>velop these new tools and help is nee<strong>de</strong>d.<br />
• Physical characterisation of Exoplanets (long term: 2009-2010)<br />
LAOG is PI in two major projects for future instruments that will allow to study the physics of extrasolar<br />
planets: Planet Fin<strong>de</strong>r (a second generation AO system for the VLT telescope), and VITRUV (a<br />
second generation, multi telescope recombiner for VLTI). These instruments are expected to provi<strong>de</strong> direct<br />
images and low-resolution spectroscopy of exoplanets. Today, the expertise to exploit these data sets does<br />
not exist at LAOG. Acquiring this expertise in complex data reduction and in planetary physics is a top<br />
long-term priority for FOST and for LAOG.<br />
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Chapter 8<br />
Appendices<br />
8.1 Members of FOST<br />
8.1.1 Permanent staff<br />
— Jean-Charles Augereau (CNAP AA)<br />
— Françoise Beck (UJF MdC)<br />
— Jean-Philippe Berger (CNAP AA)<br />
— Hervé Beust (CNAP AA)<br />
— Jean-Luc Beuzit (CNRS CR1)<br />
— Jérôme Bouvier (CNRS DR2)<br />
— Almas Chalabaev (CNRS CR1)<br />
— Alain Chelli (CNAP A)<br />
— Xavier Delfosse (CNAP AA)<br />
— Catherine Dougados (CNRS CR1)<br />
— Gaspard Duchêne (CNAP AA)<br />
— Gilles Duvert (CNAP A)<br />
— Thierry Forveille (CNAP A, on leave at CFHT)<br />
— Nicolas Grosso (CNRS CR1)<br />
— Anne-Marie Lagrange (CNRS DR1)<br />
— Fabien Malbet (CNRS CR1)<br />
— François Ménard (CNRS CR1)<br />
— Jean-Louis Monin (UJF Pr)<br />
— Estelle Moraux (UJF MdC)<br />
— Christian Perrier (CNAP A)<br />
8.1.2 Post-docs<br />
— David James: (EC-RTN FP5)<br />
— Claudio Zanni: (JETSET, joint w/SHERPAS)<br />
— Tim Kendall: (Ministry of Education)<br />
— Willem Jan De Wit: (CNRS fellowship)<br />
— Hi<strong>de</strong>ki Ozawa: (Society for the Promotion of Science, Overseas Research Fellowship, Japan, and CNAP)<br />
— Sylvia Alencar: (Brasilian fellowship)<br />
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8.1.3 Graduate Stu<strong>de</strong>nts<br />
Completed PhD’s<br />
— [2002]: Regis Lachaume. [2002-2005]: Postdoc in Bonn, Germany; [2005-2007]: Postdoc in Morelia, Mexico<br />
— [2003]: Estelle Moraux. [2005] hired as assistant professor UJF<br />
— [2003]: Gaël Chauvin. [2003-2005]: Postdoc at ESO, Chile.<br />
— [2004]: Hervé Bouy.[2004-2005]: Post-doc IAC, Spain; [2006-2007]: UC Berkeley<br />
— [2004]: Lydie Marchal. [2005-...]: High school physics teacher<br />
— [2004]: Eric Tatulli. [2005-...]: Postdoc Arcetri, Italy<br />
Ongoing PhD’s<br />
— Vanessa Agra Amboage: (FP6 RTN JETSET grant)<br />
— Myriam Benisty: (jointly w/ GRIL)<br />
— Nicolas Bessolaz: (jointly w/ SHERPAS)<br />
— Xavier Bonfils:<br />
— Philippe Delorme:<br />
— Franck Galland:<br />
— Carla Gil: (jointly w/ ESO)<br />
— Sylvain Guieu:<br />
— Emilie Herwats: (on Belgian grant)<br />
— Guillaume Montagnier: (jointly w/ GRIL)<br />
— Nicolas Pesenti:<br />
— Christophe Pinte:<br />
— Remi Reche:<br />
— Gustavo Rojas: (jointly w/ Sao Paolo University)<br />
8.2 Awards and Prizes<br />
Jérôme Bouvier – The Paul Doistau-Emile Blutet prize from the French Académie <strong>de</strong>s Sciences was awar<strong>de</strong>d<br />
to Jérôme Bouvier in 2002 for his important contribution in the discovery of brown dwarfs in open clusters and<br />
measurement of the lower IMF.<br />
Anne-Marie Lagrange – The Cino Del Duca prize from the French Académie <strong>de</strong>s Sciences was awar<strong>de</strong>d to<br />
Anne-Marie Lagrange in 2005 for her leading role in the search and <strong>de</strong>tection of Exoplanets in France.<br />
Fabien Malbet – The compaq prize (awar<strong>de</strong>d un<strong>de</strong>r the auspices of “La Société Française d’Astronomie et<br />
d’Astrophysique (SF2A)) was awar<strong>de</strong>d to Fabien Malbet in 2003 for his pionneering contribution in long-baseline<br />
near-infrared interferometry applied to the study of young stars.<br />
Jean-Louis Monin – Jean-Louis Monin was nominated a Junior Member of the Institut Universitaire <strong>de</strong><br />
France (IUF) from 1997 to 2003 (nominal 5 years, interrupted 2 years when he was a scientific director at the<br />
French ministry of research).<br />
105
106
Part V<br />
TEAM GRIL<br />
The first fringes of AMBER on the VLTI auxiliary telescopes<br />
107
108
Chapter 9<br />
Presentation of the team<br />
9.1 Foundation<br />
In the early 90’s, because of the local context and a strong political will at the local, regional and national levels,<br />
boosted by the increasing success of IRAM (whose activities LAOG was inten<strong>de</strong>d to back at its creation), the<br />
LAOG has built a capacity to get strongly involved in instrumental work for interferometry: research and <strong>de</strong>velopment<br />
on one hand, with tight interaction with physics laboratories and industry, realization of instruments<br />
for large equipments, with ESO VLTI at the first place on the other hand. It was then specifically oriented<br />
toward interferometry instrumentation because of the positive momentum created with IRAM and the urgent<br />
need that a French laboratory be more strongly involved in this field (optically oriented). In<strong>de</strong>ed, in this period,<br />
the first engineers recruitment at LAOG was inten<strong>de</strong>d for supporting the expected effort in VLTI instrumentation.<br />
While recruitment and equipment acquisition were continuously backed for years by the tutellae (mostly<br />
CNRS), the VLTI operation was <strong>de</strong>layed for some years (due to political <strong>de</strong>cisions by ESO and member states).<br />
Then the involvement turned instead to adaptive optics equipment (the GraF spectro-imager for ESO and then<br />
the NAOS adaptive optics system for the VLT) and to instrumental research, i.e. research and <strong>de</strong>velopment<br />
(R&D) activities and - a quite specific characteristic - technological research (R&T), oriented toward <strong>de</strong>tectors<br />
then integrated optics.<br />
Until 2002, the laboratory size, and specially the technical manpower, has continuously increased to achieve<br />
the foreseen goals. The range of activities and their importance in the laboratory politics became such that the<br />
need for a team oriented toward ”instrumental research” became obvious. Such a team, called GRIL for Group<br />
of Instrumental Research of LAOG has then been created in early 2004. All LAOG researchers or engineers<br />
involved in R&D or instrumental strategic discussions are supposed to participate to GRIL activities together<br />
with stu<strong>de</strong>nts who have a substantial involvement in R&D <strong>de</strong>velopments (see section 14.1).<br />
As for the other LAOG teams which have their own specificity, the instrumental research conducted by<br />
GRIL can be dictated by different orientations, for instance <strong>de</strong>fined at another level for the benefit of a larger<br />
community. However, when it comes to the actual building of instruments, LAOG will want to keep an interest<br />
in their scientific exploitation.<br />
9.2 A specific expertise<br />
The present activities of GRIL are closely related to the more-than-10 years <strong>de</strong>velopment of instrumental and<br />
technological projects in LAOG. Because of its history, expertise and equipment now available are markedly<br />
oriented toward high angular observation techniques and related technological research. Instruments like NAOS<br />
or AMBER do follow the rule while, occasionally, we may handle other projects types (e.g. WIRCAM).<br />
Therefore, LAOG has acquired special expertise on the following topics : adaptive optics (system <strong>de</strong>sign, wavefront<br />
sensors, <strong>de</strong>formable micro-mirrors), integrated optics components for interferometry (conceptual <strong>de</strong>sign,<br />
characterization, test), large instrument sub-systems <strong>de</strong>sign and interfacing, system and sub-system management,<br />
integration and test, instrumental control, interferometric data treatment. LAOG now has the appropriate<br />
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equipments for these tasks, from <strong>de</strong>dicated <strong>de</strong>sign software to adapted laboratories and an integration hall.<br />
The use of radio-submm and optical interferometers by LAOG researchers has brought an excellent knowledge<br />
of interferometric data processing. This was the rationale for creating in <strong>Grenoble</strong> a center of expertise in this<br />
field (in 2000), aimed at providing software tools for the optimum use of large optical interferometers. Other<br />
laboratories joined the process which became in 2003 the J.-M. Mariotti Center (we owe to Mariotti, a colleague<br />
of many at LAOG, a large part of the actual VLTI concept), labeled as a ”Groupement <strong>de</strong> Recherche” by CNRS.<br />
9.3 Organization<br />
GRIL, as other teams, has working meetings to discuss progress in R&D activities and instrumental <strong>de</strong>velopment.<br />
Because of the relation between the GRIL activities strategy and the politics of LAOG in terms of instrumental<br />
projects, technical staff evolution and technical equipment, GRIL has a specific role in the laboratory in relation<br />
with the instrumental research and instrumental <strong>de</strong>velopment mid to long range prospective. To this end, it<br />
schedules <strong>de</strong>dicated brain-storming meetings for discussions of this kind aimed at making propositions to the<br />
laboratory. For short term questions, that frequently arise in R&D and instrumentation matters, a board ma<strong>de</strong><br />
of three GRIL representatives and the management allows cross-information and <strong>de</strong>cision-making.<br />
9.4 Related activities<br />
• Teaching activities: Members of GRIL, even not ”maitre <strong>de</strong> conférences” or ”professeur” may be involved<br />
in teaching duties in <strong>Grenoble</strong> universities (Université Joseph-Fourier, Institut National <strong>de</strong> Physique <strong>de</strong><br />
<strong>Grenoble</strong>, ...) related to their instrumental expertise.<br />
• PhD education: through PhDs in the team, a number of young scientists have benefited from the combination<br />
of instrumentation skills and astrophysical expertise practiced in GRIL; as a result, the team is<br />
quite efficient in terms of participation in all aspects of large instruments <strong>de</strong>velopment, from conceptual<br />
and technical <strong>de</strong>sign to their optimized exploitation.<br />
• Education: The LAOG has been the main organizer of the EuroWinter School of Les Houches Observing<br />
with the Very Large Telescopes Interferometer.<br />
• Special duties: one should point out that part of the Astronomers’ instrumental involvement is service<br />
tasks rather than research ; this part takes place in the framework Observing Services of the astronomers<br />
( Instruments for TGE like VLT or CFHT, JMMC). Moreover several members of GRIL insure science<br />
administration duties at the national level (ASHRA, PNPS,...) and the European level (OPTICON).<br />
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Chapter 10<br />
Scientific rationale<br />
10.1 Background<br />
10.1.1 Key astrophysical questions<br />
The thematic priorities of the other LAOG teams point toward a number of instrumental needs, too large for<br />
an even big laboratory to cope with. For historical reasons and complementarity with other institutes, in the<br />
early 90’s the LAOG has focused its instrumental interest on the capability to study compact sources : environment<br />
of stars, especially young ones, (FOST) or AGN (SHERPAS) mainly, but also micro-quasars (SHERPAS)<br />
or embed<strong>de</strong>d protostars (ASTROMOL). Recently, with the advent of improved observational techniques (e.g.<br />
high contrast imaging with adaptive optics) that already let to spectacular results in the field, the LAOG has<br />
put forward the case of extra-solar planets.<br />
Studying the nearby environment of young stars with emphasis on extra-solar planetary systems calls first for<br />
imaging capabilities with spectral resolution and high angular resolution. Further progress will come from improving<br />
i) the achievable contrast ii) the imaging capabilities (e.g. measurement of interferometric phase) iii)<br />
the angular resolution.<br />
As a result, based on the instrumental expertise acquired in LAOG for more than 10 years, we have focused our<br />
<strong>de</strong>velopments on optical instrumentation <strong>de</strong>dicated to making progress in these directions. In parallel, some<br />
of us are or should be involved in other instrumental operations also related to studies of extra-solar planets,<br />
planetary formation or stellar formation (astrometry, high spectral resolution, radial velocity spectroscopy...)<br />
but that are outsi<strong>de</strong> our main instrumental objectives.<br />
10.1.2 Related instrumental evolution<br />
More specifically, two instrumental fields are currently evolving in the right direction to this end :<br />
• In adaptive optics (AO) imaging, continuing system and sub-systems <strong>de</strong>velopments are being done on<br />
major aspects : components (among which <strong>de</strong>formable micro-mirrors), fast low-cost computers, optimization<br />
mo<strong>de</strong>s (such as high contrast AO, or extreme AO (XAO), multi-conjugate AO), laser gui<strong>de</strong> star for<br />
wavefront sensing in empty fields. . .<br />
Part of this progress is essential to our scientific goals, especially <strong>de</strong>formable mirrors with large actuators<br />
number and the XAO approach.<br />
• Optical multi-telescope interferometry has also evolved a lot in a few years with major equipments (such<br />
as VLTI) now offered to the general User. Further improvement is to come from spectacular progress<br />
in R&D on gui<strong>de</strong>d optics, especially integrated optics, with the prospect that much of the present-day<br />
components of an instrument be accommodated within one or a few stable and very small integrated<br />
optics components.<br />
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10.1.3 Current trend of large equipments<br />
For our strategy, it is crucial to analyze the current long-term evolution towards larger and larger equipments.<br />
30-60m large optical telescopes and large ground or space interferometers are prominent projects in the domain<br />
of interest for us, and will probably largely impact the future <strong>de</strong>velopment priorities at national levels and<br />
further.<br />
To stay within the instrumental domain <strong>de</strong>fined above, it must be noted that this new generation of projects<br />
inclu<strong>de</strong>s the following instrumental cases :<br />
• coronographic extreme-AO mono-pupil imaging (VLT-PF, EPICS) or nulling interferometers (PEGASE<br />
or ALLADIN, DARWIN) to get access to very faint nearby features or companions<br />
• arrays with large number of telescopes allowing for better u,v-plane coverage (VITRUV, KEOPS)<br />
• kilometric arrays (ground or space) for access to extremely high angular resolution (OHANA-type mo<strong>de</strong>s,<br />
KEOPS)<br />
10.1.4 Increasing networking process<br />
Another crucial aspect of the context is the continuing networking process at work at various levels. Within<br />
Europe, thanks to the political will, new tools were ma<strong>de</strong> accessible to research within the 5th and 6th framework<br />
programs (FP5, FP6) notably. A I3 network, OPTICON, has permitted to finance several international<br />
collaborations connected to this discussion, for AO, fast-<strong>de</strong>tectors and interferometry software <strong>de</strong>velopment for<br />
instance. Recently an additional but smaller network, ARENA, has been accepted for specific preparation of<br />
the Antarctic use by astronomers.<br />
The prospect of the 7th framework program (FP7) being even better financed lets anticipate that part of our<br />
activities might be supported by such European funds.<br />
At the national level, an important structuration is also at work, with for instance the ”action spécifique” HRA<br />
(ASHRA) that provi<strong>de</strong>s projects evaluation (before funding) for INSU. A very successful result is to be found in<br />
the creation of the JMMC, a national network inten<strong>de</strong>d to provi<strong>de</strong> software tools to the general User of optical<br />
interferometers. It must be mentioned that we are involved in a network (through ANR fund request) <strong>de</strong>dicated<br />
to medication applications of adaptive optics techniques.<br />
10.2 Strategy<br />
10.2.1 Well <strong>de</strong>fined priorities<br />
We intend to follow the same direction as during the current ”quadrennial contract” that is focused on compact<br />
sources and specially the nearby stellar environment and their planets, but with a further emphasis on research<br />
and study of extra-solar planets, planetary systems and their formation. In this way, while fulfilling some needs<br />
of all teams, as previously seen, we give more attention to an important objective of the FOST team with the<br />
belief that LAOG may bring an important and visible contribution to the field.<br />
As seen above, the result of this choice lies on three distinct families of observational capabilities:<br />
• very high contrast imaging using coronographic AO systems or nulling interferometers, <strong>de</strong>pending on the<br />
angular resolution nee<strong>de</strong>d,<br />
• imaging capabilities of complex objects at high angular resolution calling for arrays with a larger number<br />
of telescopes than present-day interferometers,<br />
• extremely high angular resolution only accessible through kilometric-size type arrays (on the ground or in<br />
space).<br />
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The first and last items are a <strong>de</strong>finitive need for the study of extra-solar planets while the second is more<br />
of interest for stellar formation (and AGN) studies in general since the complex topographic nature of nearby<br />
environment of young stars cannot rely on mo<strong>de</strong>l fitting only and rather requires real imaging capabilities.<br />
In addition, if low to medium spectral resolutions are nee<strong>de</strong>d for most of the objectives, in stellar formation<br />
studies, a spectro-imaging approach, combining both high angular resolution within not a too small field and a<br />
spectroscopic analysis of each resolution pixel, would be i<strong>de</strong>al.<br />
It must be noted that all instrumental approaches useful for extra-planetary studies are not retained : for<br />
instance, astrometric capabilities, that are expected to be quite productive in some years from now but have<br />
been chosen as their priority by other institutes.<br />
The guiding or<strong>de</strong>rs of magnitu<strong>de</strong> Let’s recall the basic numbers that gui<strong>de</strong>d the high-level <strong>de</strong>finition of<br />
the current instrumentation for these priorities to be followed.<br />
• Spectral range: in the range 1-2.5 µm (J, H and K bands), emission is at 1000 K to 3000 K; going further<br />
allows to probe cooler material and going shortward allows to probe the important region around Hα.<br />
• Spatial resolution: in nearby (100 pc) star formation regions, 1 mas typically corresponds to 0.10 AU.<br />
Investigating planet formation requires at least one milliarcsec resolution. At the wavelengths quoted<br />
above, this implies interferometric baselines of about one hundred meters. In AGN, the outer size of dust<br />
tori are expected to be around 3 pc. Since 10 mas @ 15 Mpc (closest AGN) corresponds to 0.5 pc, the<br />
same resolution power is necessary.<br />
• Sensitivity: YSO are fainter than K=5 and AGN than K=7-9. The required instrumentation is directly<br />
constrained by this sensitivity threshold<br />
• Accuracy: in AGN and YSO, the requested dynamic range is of the or<strong>de</strong>r of 1:100 to 1:1000. For the<br />
exoplanets, the brightest Pegasids are almost 10 4 times fainter than their host stars (at 2 µm). Therefore<br />
a measurement accuracy between 1% and 0.1% is compulsory and better is required for some specific<br />
objectives.<br />
10.2.2 Focusing on three complementary axii<br />
The exposed priorities lead to the following possible directions of instrumental <strong>de</strong>velopment, constrained by<br />
the high-level requirements above mentioned, organized here in the three complementary families previously<br />
analyzed :<br />
• Improving Very High Contrast imaging capabilities Associated to a typically low spectral resolution,<br />
VHC imaging points toward optimized AO-based imagers like the VLT Planet Fin<strong>de</strong>r (2 nd generation<br />
VLT instrumentation) or nulling-type interferometers like, in the long term, DARWIN or TPF-I whose<br />
precursors could be the PEGASE project proposed to CNES in the context of the free-flyers CfT or the<br />
GENIE-on-ice ALLADIN project for Antarctica. The related <strong>de</strong>velopments are : Adaptive optics with<br />
large number of actuators, system studies or sub-systems (e.g. fast <strong>de</strong>tectors) for VHC contrast imaging<br />
optimization, integrated optics at thermal wavelengths optimized for excellent characteristics (of spatial<br />
filtering, low level of leakage for instance).<br />
• Improving imaging capabilities of complex objects Associated to low-to-medium spectral resolution,<br />
better imaging capabilities of interferometers point toward an increase of the number of baselines ;<br />
while present-day optical interferometers (IOTA with IONIC, VLTI with AMBER, CHARA with MIRC)<br />
are just beginning using closure phase with three telescopes, there is a good prospect for increasing the<br />
u,v-plane coverage as the PdB IRAM interferometer did in the past when going from the initial 3 antennae<br />
to the current 6 antennae, i.e. a factor x15 in the phase information level. The related <strong>de</strong>velopments are :<br />
continuing integrated optics <strong>de</strong>velopment toward more complex and performant components (recombinators<br />
with 4, 6 or 8 beams ; improved throughput ; other functionalities like optimized fringe tracking<br />
components) ; AO system <strong>de</strong>velopment <strong>de</strong>dicated to large interferometers auxiliary telescopes.<br />
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• Improving High Angular Resolution observation capabilities The goal is here to go beyond the<br />
current limit (typically several milliarcsec at J to K with the VLTI), requiring kilometric baselines for<br />
near-IR interferometry (providing down to 10 − 4 arcs) ; it can also be, operational constraints permitting,<br />
to use (segments of) large single-dish telescopes (ELT-type, un<strong>de</strong>r completion phase) at visible wavelengths<br />
by pupil masking techniques until AO systems can work at V on large telescopes. The related<br />
<strong>de</strong>velopments are also to be found in progressing in integrated optics on one hand, in progressing on the<br />
system optimization nee<strong>de</strong>d for combining AO use with pupil masking on the other hand.<br />
10.2.3 The principles of our involvement<br />
Our philosophy is based first on the acquired experience in <strong>Grenoble</strong> of course but also in other places :<br />
high angular resolution techniques are complex and benefit must be taken from all the available experience<br />
accumulated in the laboratory or on the sky. Our <strong>de</strong>velopments in integrated optics (such as the IONIC longterm<br />
R&D) were tightly based on the anterior work on FLUOR at Observatoire <strong>de</strong> Paris while the <strong>de</strong>sign of a<br />
large AO-based instrument (like NAOS) was based on the successful approach followed for ADONIS at ONERA<br />
and Observatoire <strong>de</strong> Paris.<br />
As a result, we want to reach the best coherence possible of our strategy with the national instrumental politics.<br />
As previously remin<strong>de</strong>d, this one is well structured at the national (or international) level so that our own<br />
views are regularly confronted with the perspectives at this higher level and, for R&D notably, more and more<br />
<strong>de</strong>fined within the context of networks. Because of this and of the increasing complexity and cost of the TGE<br />
general-User instruments, LAOG naturally acts within consortia for large projects.<br />
The second guiding principle is to keep a good balance between instrumental research and involvement in large<br />
instruments operations. A major, and rather specific, element in the LAOG strategy is in the strong willing to<br />
keep this balance in the long-term since it provi<strong>de</strong>s very useful inputs, drawn from R&D results, to conceptual<br />
studies of future large instruments. It is also a <strong>de</strong>terminant piece of politics for the resources management. In<br />
practice, LAOG may program one to two large projects in parallel to R&D programmes.<br />
A third elements of politics is our intention to keep involved in spatial projects through R&D contracts where<br />
our expertise in system conception and specific components <strong>de</strong>velopment and characterization can be useful.<br />
The question to get even more involved in the future is open, <strong>de</strong>pending on the technological orientation of<br />
space projects.<br />
10.2.4 A logical sequence<br />
To make it robust, the LAOG has always tried – and wants to do so in the future - to built its <strong>de</strong>tailed strategy<br />
on the wish to participate in the whole sequence of phases that go from instrumental research to general-use<br />
instruments on TGE. This insures the best transfer of expertise from the technological field to the instrumental<br />
<strong>de</strong>sign. The <strong>de</strong>cision to get involved in given projects is therefore largely constrained by continuity needs : it<br />
can be seen in the graph (Figure 10.1 that the projects IONIC, IONIC/CHARA, VITRUV belong to such a<br />
sequence, as do IODA, PEGASE, DARWIN, or MMD, <strong>de</strong>dicated AO systems, or also NAOS, VLT-PF, EPICS.<br />
With appropriate collaborations, the goal to participate in each phase of such sequences, i.e. of a given instrumental<br />
objective, can be met provi<strong>de</strong>d that R&D be based on the present expertise at LAOG and that,<br />
obviously, large instruments be selected by agencies for funding. It must be noted that this strategy implies<br />
a commitment to already engaged operations. The VLT-PF for instance results from a 3-years long pre-study<br />
and, providing <strong>de</strong>cision is confirmed in late 2005, implies the LAOG commitment.<br />
The resulting strategy can be summarized as follows, by emphasizing the priorities that were followed during<br />
the current ”quadrennial period”:<br />
• strengthening our efforts in R&D on IO for interferometry aiming both at <strong>de</strong>veloping 2 µm imagers<br />
(VITRUV) and progressing towards 10 µm nulling interferometry (DARWIN)<br />
• <strong>de</strong>veloping a new technology of <strong>de</strong>formable mirrors in view of the instrumental needs of ELT as well as<br />
small telescopes<br />
• taking benefit of the expertise acquired with NAOS to promote a concept of extreme AO-based imager<br />
(VLT-PF)<br />
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Figure 10.1: The logical link between past or engaged R&D and instruments organized according to the three<br />
families: adaptive optics, interferometry, <strong>de</strong>tectors and cameras. The logics <strong>de</strong>scribed in the text is ma<strong>de</strong> visible:<br />
for instance, how NAOS building prepared us to promoting the VLT-PF, the VLT-PF pre-studies prepared those<br />
on EPICS for an ELT; the same applies with AMBER now followed by VITRUV, which in turn benefits from<br />
the success of IONIC-type R&D. In addition, related R&D activities are grouped within boxes to make their<br />
connection clear. It must be emphasized that the various projects shown belong to only three different families,<br />
each with R&D and instrumentation, that are largely focused on <strong>de</strong>cisive progress in eitheir very high contrast<br />
imaging, imaging capabilities or very high angular resolution observations<br />
• providing a 2 µm 3-beams spectro-imager (AMBER) to ESO and use the experience of it to study and<br />
promote a faster imager (VITRUV) for the VLTI.<br />
It is very satisfying to notice and recognize that all of these goals, presented in the previous LAOG evaluation,<br />
have been met as can be seen in the next chapter.<br />
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Chapter 11<br />
Results<br />
11.1 Towards high dynamic with Adaptive Optics (AO)<br />
The LAOG adaptive optics activity is actively contributing to the <strong>de</strong>velopment of the current European efforts<br />
to provi<strong>de</strong> more efficient and performant adaptive optics (AO) systems for astronomy, but also for other applications,<br />
such as ophthalmology, laser beam shaping, etc. In or<strong>de</strong>r to achieve these goals, LAOG is mainly acting<br />
in two different directions, i/ the <strong>de</strong>velopment of new components for the future generations of AO systems and<br />
ii/ the contribution to the manufacture of AO instruments for ESO with other French and European partners.<br />
11.1.1 The first generation: NAOS<br />
The NACO instrument on the VLT UT-4 telescope consists of the NAOS adaptive optics system, providing<br />
diffraction-limited images in the near infrared, and of its companion science camera, CONICA, equipped with a<br />
1024 × 1024 ALLADIN <strong>de</strong>tector covering the 1–5 µm spectral domain (Figure 11.1). CONICA was <strong>de</strong>veloped<br />
un<strong>de</strong>r the responsibility of the Max-Planck Institute for Astronomy in Hei<strong>de</strong>lberg. The main technical features<br />
of NAOS are a piezo-stack <strong>de</strong>formable mirror with 185 actuators and a separate tip-tilt mirror, two selectable<br />
Shack-Hartmann wavefront sensors operating either in the optical (450-950 nm) or in the near-IR (800-2500<br />
nm) range, both featuring up to 14 × 14 sub-apertures. NAOS has been manufactured by a French consortium<br />
including ONERA, Observatoire <strong>de</strong> Paris and LAOG. LAOG was in charge of the <strong>de</strong>sign and manufacturing of<br />
the opto-mechanical structure (P. Rabou; E. Stadler), the instrument control system (J. Charton), the visible<br />
wavefront sensor (P. Feautrier) and the integration and tests of the whole instrument in its static mo<strong>de</strong>, i.e.<br />
without the AO components 1 (P. Kern; P. Puget). LAOG was also responsible for the NAOS Science Group (A.-<br />
M. Lagrange Project Scientist) and therefore LAOG scientific staff was heavily involved in the commissioning<br />
activities 2 (J.-L. Beuzit, G. Chauvin, D. Mouillet - Figure 11.2). NAOS and CONICA are now wi<strong>de</strong>ly used by<br />
the ESO community amongst which several LAOG astronomers (cf. FOST).<br />
11.1.2 The high contrast imaging: VLTPF<br />
For its second generation instrumentation on the VLT, ESO has supported two 2-year concurrent Phase A<br />
studies for a so-called ”Planet Fin<strong>de</strong>r” <strong>de</strong>dicated instrument, the first one led by the Max-Planck Institute for<br />
Astronomy in Hei<strong>de</strong>lberg and the second one led by LAOG (P.I. J.-L. Beuzit). The prime objective of such an<br />
instrument for the VLT, initially proposed by LAOG (D. Mouillet) will be the discovery and study of new giant<br />
extra-solar planets orbiting stars, by direct imaging of the circumstellar environment. The challenge consists<br />
in the very large contrast between the host star and the planet, larger than ∼ 12.5 magnitu<strong>de</strong>s at very small<br />
1 Charton J., Hubert Z., Stadler E., Schartz W., Beuzit J.-L., 2003, System level simulation of micro-mirrors for adaptive optics<br />
in Specialized Optical Developments in Astronomy. Atad-Ettedgui, E.; D’Odorico, S. Ed.. SPIE Proc., 4842, 207-218.<br />
2 Mouillet D., Lagrange A. M., Beuzit J.-L., Moutou C., Saisse M., Ferrari M., Fusco T., Boccaletti A., 2004, Extra-solar Planets:<br />
Today and Tomorrow in High Contrast Imaging from the Ground: VLT/Planet Fin<strong>de</strong>r; ASP Conf. Ser. 321, 39.<br />
116
Figure 11.1: NAOS-CONICA installed on the Nasmyth B platform of the 8.2-m VLT YEPUN Unit-4 Telescope.<br />
From left to right: the telescope adapter/rotator (dark blue), NAOS (light blue) and the CONICA cryostat<br />
(red). The control electronics is housed in the white cabinet.<br />
angular separations, typically insi<strong>de</strong> the seeing halo. Therefore the whole <strong>de</strong>sign of such an instrument shall<br />
be optimized towards reaching the highest contrast performance in a limited field of view and at the shortest<br />
possible distances to the central star. Keeping this prime objective in mind, it is obvious that many other<br />
research fields will also benefit from the instrument performance, in the domains of brown dwarf studies, protoplanetary<br />
disks, mass loss of stars, etc. The Planet Fin<strong>de</strong>r instrument will greatly contribute to the next 10<br />
years of studies in the research field of extra-solar planets, already very active, particularly by offering the first<br />
direct <strong>de</strong>tections of planets more massive than Jupiter at various stages of their formation, in the key separation<br />
range of 1 to 100 AU. Migration mechanisms could then be better un<strong>de</strong>rstood. The complementarities of direct<br />
imaging with other <strong>de</strong>tection methods, in terms of targets, <strong>de</strong>tection biases and measured planetary parameters,<br />
and more specifically, the combination with other projects like HARPS, COROT, VLTI/PRIMA, JWST and<br />
Kepler will offer promising new avenues in this field. The present indications that massive distant planets could<br />
be numerous will be firmly confirmed or <strong>de</strong>nied by the Planet Fin<strong>de</strong>r, if the number of observed targets with<br />
relevant <strong>de</strong>tection limits is statistically acceptable, i.e. greater than typically 200. This would in particular<br />
fully justify a large effort in an exten<strong>de</strong>d observational survey of several hundred nights.<br />
The key features of such an instrument inclu<strong>de</strong> an extreme AO system allowing to reach Strehl ratios of 90% in<br />
the H band un<strong>de</strong>r reasonably good seeing conditions, a coronagraphic module, harboring a classical Lyot <strong>de</strong>vice<br />
as well as one or two phase mask <strong>de</strong>vices (4-quadrant phase mask and/or apodized Lyot for instance) allowing<br />
to reach very small angular separations between the host star and the planet candidates, a differential imaging<br />
camera <strong>de</strong>dicated to infrared imaging in one or two simultaneous spectral bands or two orthogonal polarization<br />
as well as low resolution long slit spectroscopy (R ∼ 50 to 500). For stability reasons, the instrument will not be<br />
directly attached to the telescope Nasmyth rotator but rather installed on the Nasmyth platform. All the above<br />
<strong>de</strong>scribed modules and sub-systems will be located on a fixed bench, controlled for vibrations and temperature<br />
variations and equipped with an environment control.<br />
117
Figure 11.2: NAOS-CONICA image of the double star GJ 263 for which the angular distance between the two<br />
components is only 0.030 arcsec. The raw image, as directly recor<strong>de</strong>d by CONICA, is shown in the middle, with<br />
a computer-processed (using the ONERA MISTRAL myopic <strong>de</strong>convolution algorithm) version to the right. The<br />
recor<strong>de</strong>d Point-Spread-Function (PSF) is shown to the left. The CONICA pixel scale of 0.01325 arcsec/pixel<br />
was used with the FeII filter (1.257 µm). The exposure time was 10 seconds. This image was obtained during<br />
the NAOS/CONICA commissioning run in November 2003.<br />
Following presentations of the results of our phase A study to an ESO-appointed Review Board in December<br />
2004 and to the ESO Scientific and Technical Committee in April 2005, our proposal has been recommen<strong>de</strong>d for<br />
phase B. We are currently preparing the contract for this phase B with ESO and also consi<strong>de</strong>ring the possibility<br />
to inclu<strong>de</strong> members of the competing team in or<strong>de</strong>r to broa<strong>de</strong>n the capabilities of the Planet Fin<strong>de</strong>r instrument.<br />
First light of the Planet Fin<strong>de</strong>r is foreseen to occur by end of 2009 or beginning of 2010.<br />
11.1.3 Instrumental Research and <strong>de</strong>velopment activities<br />
DEFORMABLE MICRO-MIRRORS<br />
The LAOG R&D activities in adaptive optics are focused on the <strong>de</strong>velopment of new <strong>de</strong>formable mirrors for the<br />
next generation of AO systems. The goal is two-fold: i/ obtain smaller and cheaper mirrors for astronomical<br />
applications such as AO systems for interferometry, Multi-Object Adaptive Optics (MOAO) systems, etc., or<br />
for non astronomical applications like ophthalmology, laser beam shaping, telecommunications; ii/ manufacture<br />
mirrors with several thousands actuators for astronomical applications in the fields of eXtreme AO, AO systems<br />
for the Extremely Large Telescopes (ELT), etc. These innovative works lead to three patents and two technology<br />
transfer during the 2001-2005 period (see 14.3).<br />
Magnetic <strong>de</strong>formable mirrors This technology is particularly well adapted to the production of low or<strong>de</strong>r,<br />
large stroke mirrors, therefore allowing to correct all wavefront errors without the need for the usual second tiptilt<br />
stage. These mirrors will for instance be used for interferometry, MOAO, ophthalmology, laser beam shaping,<br />
etc. We have already produced several 52-actuator <strong>de</strong>vices (Figure 11.3), including their control electronics,<br />
and we are now offering these <strong>de</strong>vices through two commercial partners (see below and in section 14.3). Further<br />
<strong>de</strong>velopments are consi<strong>de</strong>red in or<strong>de</strong>r to increase the number of actuators up to 400. The typical characteristics<br />
of these mirrors are given below:<br />
• the minimum actuator step is 2 mm with the current technology<br />
• the typical best-flat surface is ∼ 5 nm RMS (mirror surface)<br />
• typical strokes for the low or<strong>de</strong>r mo<strong>de</strong>s range from 10 to 15 µm (possibly up to 100 µm)<br />
• the linearity remains below 2% for large strokes (below 1% for +/- 5 µm stroke)<br />
118
Figure 11.3: Left: the first 52-actuators magnetic <strong>de</strong>formable mirror prototype. Right: the MEMS-based<br />
electrostatic <strong>de</strong>formable mirror prototype<br />
• there is no measurable hysteresis<br />
• the mirrors can be used in systems with a typical rejection bandwidth of 100 to 200 Hz<br />
• standard coatings such as protected silver can be applied on the mirror membrane<br />
Electrostatic <strong>de</strong>formable mirrors The second technology is based on MEMS (Micro Electro Mechanical<br />
System) technology. It is first targeted at high performance applications needing a very large number of actuators,<br />
but we keep it compatible with potentially high volume applications such as ophthalmology. This<br />
compatibility allows us to use high-end manufacturing facility at CEA-LETI, that would otherwise be inaccessible.<br />
The current prototype, based on a novel (patented) actuator concept is being tested at LAOG. It already<br />
shows unique features, such as a large stroke (5 µm) with a truly continuous optical surface. This <strong>de</strong>velopment<br />
is now being fun<strong>de</strong>d by EC as a specific OPTICON JRA1 workpakage, led by LAOG. Our goal is to provi<strong>de</strong> a<br />
2000-actuator <strong>de</strong>formable mirror by the end of 2007.<br />
Industrial <strong>de</strong>velopment These innovative works led to three patents and two technology transfers during<br />
the 2001-2005 period (see the <strong>de</strong>tails in 14.3). The production and selling tasks of MMD have been transfered to<br />
two <strong>de</strong>dicated companies (FLORALIS for astronomical applications and Imagine Eyes for all other applications<br />
un<strong>de</strong>r specific licensing contracts, allowing LAOG to keep focused only on the very R&D, be it for components<br />
only until now or possibly exten<strong>de</strong>d to the full system later.<br />
OTHER TASKS<br />
Laboratory test bench As part of the prototyping efforts during the Planet Fin<strong>de</strong>r Phase A study, a simple<br />
adaptive optics test bench has been set-up at LAOG to validate various new control concepts. For instance<br />
the possibility to fully servo the position of the instrument pupil using only the data from the Schack-Hartman<br />
wavefront has been <strong>de</strong>monstrated (G. Montagnier, master thesis) using this test bench. These experimental<br />
validations were conducted in collaboration with our colleagues from ONERA (T. Fusco and M. Nicolle).<br />
Integral Field Spectroscopy with Adaptive Optics The research is progressing on the instrumental<br />
issues of the coupling of Integral Field Spectroscopy (IFS) with adaptive optics. This field of research was<br />
initiated at LAOG in 1994 with one of the first IFS instruments used with AO (GraF spectrograph successfully<br />
used with the ADONIS at the ESO 3.6m telescope 3 ) and pursued with the implementation of the GriF mo<strong>de</strong><br />
3 Chalabaev, A.; Le Coarer, E.; Rabou, P.; Magnard, Y.; Petmezakis, P.; Le Mignant, D., 2002; The GraF instrument for<br />
Imaging Spectroscopy with the Adaptive Optics, Experimental Astronomy, 2002, 14, 147<br />
119
on PUEO at CFHT. The IFS experts (A. Chalabaev and E. le Coarer) have recently contributed to the studies<br />
of the spectroscopic option for the VLT-PF instrument and are now studying the best possible integral field<br />
spectrograph <strong>de</strong>signs for ELT’s.<br />
MCAO and GLAO studies In the frame of our collaboration with ONERA, a study has been initiated on<br />
the <strong>de</strong>termination of the sky coverage for Multi Conjugate Adaptive Optics (MCAO). An optimized algorithm<br />
has been <strong>de</strong>veloped to improve previous sky coverage estimates, by more accurately accounting for instrumental<br />
and observational parameters such as the wavefront sensor concepts (star or layer oriented), the gui<strong>de</strong> stars<br />
relative positions in the field and the gui<strong>de</strong> star magnitu<strong>de</strong> histogram. This work was conducted by A. Blanc<br />
on a 2-years contract financed by ESO.<br />
Another critical point for the conception of the next generation large field adaptive optics systems is the<br />
optimization of the wavefront sensing approaches. As part of these efforts, a ONERA-fun<strong>de</strong>d PhD thesis has<br />
been started in 2003 to address this question for the particular case of Ground Layer Adaptive Optics (GLAO)<br />
systems (co-directors: by T. Fusco and J.-L. Beuzit).<br />
11.2 Bringing optical interferometry into mainstream astronomy<br />
The LAOG interferometric activities aims at bringing optical interferometry into mainstream astronomy. To<br />
fulfill this goal LAOG is carrying a multiple front effort going from instrumental research and <strong>de</strong>velopment,<br />
instrument <strong>de</strong>sign and construction to real data analysis and interpretation.<br />
Optical interferometry has been <strong>de</strong>veloped in LAOG since 1995 through the participation to the Very Large<br />
Telescope Interferometer run by ESO and national actions on GI2T and FLUOR. Then LAOG has started an<br />
R&D activity in integrated optics in 1996 and has participated in 1998 to the VLTI/AMBER instrument.<br />
11.2.1 The classical approach: AMBER<br />
AMBER is the three-telescope beam combiner for the VLTI operating in the J, H, and K bands and equipped<br />
with a spectrograph whose spectral resolution can reach 10000. It has been manufactured by a European<br />
consortium including the Observatoire <strong>de</strong> la Côte d’Azur, the Université <strong>de</strong> Nice, the Observatory of Arcetri<br />
(Italy), the Max-Planck Institute for Radioastronomie in Bonn (Germany) and the LAOG. This instrument<br />
has involved a major part of the LAOG resources during 6 years, for its <strong>de</strong>sign, its manufacturing and its<br />
integration. LAOG was in charge of the instrumental control <strong>de</strong>vice (resp. E. Le Coarer ), of the data reduction<br />
software (resp. G. Duvert), and of the assembly, integration and tests (resp. K. Perraut). The laboratory is<br />
also responsible of the lea<strong>de</strong>rship of the scientific group (F. Malbet, Project scientist) and the co-management<br />
of the projet (resp. P. Puget then P. Kern).<br />
Challenges The main challenges of AMBER consists mainly in the original <strong>de</strong>sign of such an instrument.<br />
The main i<strong>de</strong>a was to merge the French expertise in interferometry both in high precision (FLUOR experiment)<br />
and spectro-interferometry (GI2T experiment). The AMBER concept is directly inherited from these two<br />
experiments using part of their technology: optical fibers, dispersed fringes,... In addition, we have <strong>de</strong>veloped<br />
a new way to process the signal with a very strong emphasis on internal calibration of all the instrument from<br />
the entrance to the pixels. It has produced a new data reduction algorithm based on carrying waves that we<br />
have called ”Pixel-to-Visibilities” processing. This processing relies on a full calibration of the internal effects<br />
to produce a matrix of the instrumental transfer function. The complex visibility is therefore a direct product<br />
from this matrix to the flux <strong>de</strong>tected on the pixels.<br />
Current status AMBER has already produced a full hand of scientific results on the luminous blue variable<br />
Eta Carinae (Petrov et al. 2005, ESO conference), the evolved binary system Gamma Velorum (Petrov et al.<br />
2005, ESO conference), the Be star HD 50013, the young stellar system MWC 297 (Malbet et al. 2005, ESO<br />
120
Figure 11.4: Left: the AMBER instrument in the VLTI focal laboratory at the ESO Paranal VLT observatory.<br />
Right: first AMBER observations with the three Unit Telescopes on 70 Aql with the medium spectral resolution<br />
in K band. From ESO Press Release 07/04.<br />
conference) and some progress in the qualification of the instrument for exoplanet <strong>de</strong>tection. The result on<br />
MWC 297 is <strong>de</strong>veloped in the FOST part.<br />
AMBER expected on-sky performances in terms of limited magnitu<strong>de</strong>, spectral resolution and dynamic<br />
range have no equivalent. This translates into mandatory requirements for the VLTI in terms of dynamical<br />
cophasing and throughput that have not yet been met. Informations gathered during AMBER commissioning<br />
periods have been a key point to reveal current VLTI weaknesses (various sources of vibration, <strong>de</strong>gradation<br />
on PSF in the <strong>de</strong>lay-lines tunnel, etc. yielding low instrumental contrast). Much is expected from the VLTI<br />
recovery plan un<strong>de</strong>r progress in or<strong>de</strong>r for AMBER to reach its final performances.<br />
The instrument has been offered to the European astronomical community for the first time for the period<br />
P76 (starting 1st Oct 2005) and proposed again for P77. The commissioning period is still continuing with<br />
long periods of waiting for improvement of the performance of the VLTI subsystems. The VLTI is in 2005<br />
following a recovery plan that should in principle help to eventually reach the AMBER ultimate performances.<br />
Most of the remaining actions for LAOG people are now commissioning runs, data reduction, support to the<br />
astronomical community for preparing observations and optimally using the AMBER ability, science planning<br />
for the Guaranteed Time Observations (GTO) and publication.<br />
Several PhD stu<strong>de</strong>nts have taken part to this project: P. Mège at the concept study, C. Gil during integration<br />
in <strong>Grenoble</strong>, E. Tatulli and F. Millour for the data reduction algorithms. A CNRS postdoc has been hired to<br />
focus on the astrophysical interpretation of commissioning data: W.-J. De Wit. This instrument is being used<br />
by member of the FOST team and SHERPA team. An internet web site is being hosted by LAOG at the following<br />
address: amber.obs.ujf-grenoble.fr. Fabien Malbet is the main responsible for this activity at LAOG.<br />
121
Figure 11.5: Image of the binary star λ Virginis obtained by aperture synthesis with the IONIC3 instrument<br />
on IOTA. At the bottom, the beam combiner IONIC3. From Monnier et al., 2004, ApJ, 602, L57.<br />
11.2.2 The innovative integrated optics: IONIC on the IOTA and VLTI interferometers<br />
LAOG has <strong>de</strong>veloped in a close partnership with the Harvard-Smithsonian Center for Astrophysics the focal<br />
instrument (called IONIC3) combining three telescopes of the IOTA Interferometer (Traub et al., 2004, SPIE,<br />
5491, 482). This instrument, whose first light has occurred in 2002, uses the integrated optics techniques <strong>de</strong>veloped<br />
by LAOG with its local partners (IMEP and LETI) and significantly financed by the CNES. IONIC3 is the<br />
more sensitive and the more accurate imaging instrument operating in the near infrared range. It is now used<br />
by about ten American and European teams and provi<strong>de</strong>s scientific results in the field of imaging of multiple<br />
systems (Figure 11.5), pre-main sequence stars, evolved stars (Kraus et al., 2005, AJ, 130, 246). J.-P. Berger<br />
is the main responsible for this activity at LAOG.<br />
LAOG has also <strong>de</strong>livered two integrated optics beam combiners to ESO to equip the focus of the VINCI<br />
instrument. The first one, ma<strong>de</strong> by ion-exchange technique and operating in H band, has been tested at<br />
Paranal during the summer 2002 (Le Bouquin et al., 2004, A&A, 424, 719). The second one, ma<strong>de</strong> by silica-onsilicon<br />
etching technique and operating in K band, has been installed in Paranal during the summer 2004. The<br />
latter is routinely used with VINCI for VLTI test such as for the first combination of the Auxiliary Telescopes<br />
(Figure 11.6).<br />
11.2.3 Combining up to eight telescopes of the VLTI array: VITRUV<br />
In the framework of the European Interferometry Initiative (EII) within the FP6 OPTICON program (see<br />
”European involvement” chapter in this report), we have conducted the concept study for a second generation<br />
instrumentation for the VLTI. It consists of a spectro-imager based on the integrated optics techniques aimed<br />
at combining 4 to 8 beams from the VLTI to produce aperture synthesis images in one single night. The work<br />
consisted in several R&D <strong>de</strong>velopments financed by the CNES and the BQR of UJF University (4-way beam<br />
combiners, 4T/8T workbenches, end-to-end lab and numerical mo<strong>de</strong>ling, system studies, image reconstruction,<br />
...) but also the preparation of the science cases in collaboration with P. Garcia in Porto (chair of the Science<br />
group).<br />
This concept and all related studies have been presented at the ESO Workshop The Power of Optical/IR<br />
Interferometry: Recent Scientific Results and 2nd Generation VLTI Instrumentation, held in Garching in April<br />
2005. This project has been recommen<strong>de</strong>d by the Science Council of the EII to ESO, but is still waiting for the<br />
beginning of a phase A study. F. Malbet is responsible for this activity.<br />
122
Figure 11.6: Left: Integrated optics two-telescope beam combiner for the VINCI instrument of the VLTI.<br />
Right: first fringes obtained with the Auxiliary Telescopes of the VLTI on HD 62082 by means of the integrated<br />
optics beam combiner in the K band (ESO Press Release 06/05).<br />
11.2.4 Instrumental Research and <strong>de</strong>velopment activities<br />
Lab workbenches IONIC passed and future on-sky experiments rely on a intensive laboratory effort whose<br />
aim is to characterize as much as possible all the performances in lab before any shipment. This has required<br />
the <strong>de</strong>velopment of new testbeds such as an industrial level connectorization bench to plug fiber V-grooves to<br />
integrated optics chips, or a full VLTI 8-telescope simulator (Jocou et al., 2004, SPIE, 5491, 1351).<br />
An infrared camera <strong>de</strong>dicated to these interferometric workbenches has been fully <strong>de</strong>veloped in LAOG in<br />
collaboration with the LESIA (Observatoire <strong>de</strong> Paris) for the clock sequencer. This camera uses a PICNIC<br />
infrared array produced by the Rockwell Science Center in the US. The main features of this <strong>de</strong>tector are:<br />
256x256 pixels of 24 µm size, sensitive to the [0.9 µm; 2.5 µm] range, CMOS technology allowing multiple<br />
non-<strong>de</strong>structive readout and image windowing, readout noise of about 40 e − . Such a lab camera is required for<br />
the Vitruv <strong>de</strong>monstrator as well as for measuring interferometric signals coming from a 8-telescope combiner.<br />
The PICNIC camera is currently un<strong>de</strong>r its final tests: the cryogenics and the readout electronics sub-systems<br />
were successfully accepted, the first images of the whole system at cold temperature using the ”MUX” was<br />
recently obtained (electrical mo<strong>de</strong>l of the <strong>de</strong>tector used to <strong>de</strong>bug the system before using the science gra<strong>de</strong><br />
<strong>de</strong>tector). This camera will be <strong>de</strong>livered to the laboratory before the end of 2005.<br />
Integrated optics for DARWIN: MAII, IODA LAOG is involved in R&D programs <strong>de</strong>dicated to the<br />
preparation of the ESA DARWIN mission (Léger et al., 1996, A&SS, 241(1), 135). This mission is aimed at<br />
discovering life on Earth-like exoplanets and therefore is extremely challenging on the technical si<strong>de</strong>. One of<br />
the most critical concerns is the ability in this nulling experiment to perform the most efficient modal filtering<br />
to achieve very high dynamic range and main star extinction mandatory for <strong>de</strong>tection of Earth-like planets. In<br />
this context, single-mo<strong>de</strong> wavegui<strong>de</strong>s have been i<strong>de</strong>ntified as one of the most promising solutions (Ménesson et<br />
al., 2002, JOSA, 19(3), 596). On this basis of its expertise in integrated optics for interferometry, LAOG has<br />
contributed to three ESA R&D contracts <strong>de</strong>dicated to the DARWIN mission by:<br />
• providing the integrated optics beam combiner of a nulling bench in the H band in the framework of<br />
the Multi Aperture Imaging Interferometer, (MAII, an ESA contract). The project un<strong>de</strong>r direction of<br />
123
Figure 11.7: PICNIC low noise infrared camera during the integration tests, before <strong>de</strong>livery<br />
Alcatel Space Industry (ASI) was based on a large consortium 4 . Two kinds of 2-telescope beam combiners<br />
have been provi<strong>de</strong>d using the IMEP/GeeO and LETI standard telecom technologies <strong>de</strong>dicated to 1.5 µm<br />
wavelength. At the end of the contract at the beginning of 2004, we have obtained nulling at a 10 −6 level<br />
with a laser source and at a 10 −4 level with a broad band source (with a width of 100 nm), to be compared<br />
with the 10 −3 level obtained with a 20 µm-hole and a CO2 laser at 10.6 µm (Ollivier, 1999, PhD thesis).<br />
• proposing the theoretical analysis of the integrated optics capabilities in the Achromatic Phase Shifter<br />
(APS) manufacturing (a contract led by IAS, Orsay).<br />
• <strong>de</strong>veloping specific wavegui<strong>de</strong>s for the full DARWIN spectral domain (i.e. [4 µm; 20 µm]). IMEP has the<br />
lea<strong>de</strong>rship of this program with strong contributions of LETI for technology <strong>de</strong>velopments and LAOG<br />
for sample tests. ASI contributes for management tasks, and LPMC in Montpellier provi<strong>de</strong>s promising<br />
chalcogeni<strong>de</strong> technologies. This 2-year <strong>de</strong>velopment that will end in December 2005 has allowed to achieve<br />
the first single-mo<strong>de</strong> hollow-metallic wavegui<strong>de</strong>s in the mid-infrared range (Figure 11.8 - Labadie et al.,<br />
2005, A&A, in press).<br />
Post doctoral and doctoral stu<strong>de</strong>nts (P. Haguenauer, E. Laurent, L. Labadie) conducted these activities with<br />
the support of the technical team. For all of the contracts Pierre Kern was responsible for LAOG.<br />
Micro-piezoelectric fiber positioners To answer several issues about fine injection into fibers (IONIC,<br />
VITRUV), we have <strong>de</strong>veloped a new generation of micro-positioning <strong>de</strong>vices including mini-sensors for submicrometric<br />
position measurements (Preis et al., 2004, SPIE, 5491, 1379). This <strong>de</strong>vice contains a piezoelectric<br />
tube on which there are five metallic electro<strong>de</strong>s. The micro-positioning <strong>de</strong>vice will eventually be integrated in<br />
the VITRUV project in or<strong>de</strong>r to control very precisely the position of every fiber at the focus of each telescope.<br />
The responsible is O. Preis.<br />
4 (IMEP, CSO Mesure, GeeO, LETI, LAOG, ASI)<br />
124
Figure 11.8: Left panel: Process flow of Hollow Metallic Wavegui<strong>de</strong>s (HMW) manufacturing. I: Silicon 4<br />
inches wafer - II: Gui<strong>de</strong> <strong>de</strong>finition by photo-lithography and RIE - III: Thermal oxidation and gold <strong>de</strong>position -<br />
IV: Gold and silica wet etching - A: P yrex T M 4 inches wafer - B: Photo-lithography and P yrex T M wet etching<br />
- C: Gold <strong>de</strong>position - D: Photo-resist stripping - F: Anodic bonding. Middle panel: photograph of a HMW<br />
input using Scanning Electron Microscope. The Pyrex cover is maintained by anodic bonding on the silicon<br />
substrate. The etching <strong>de</strong>pth is equal to 10 µm. The gold <strong>de</strong>position is thicker on the bottom part of the<br />
wave-gui<strong>de</strong> with respect to the lateral walls. Right panel: diffraction-limited spot corresponding to the output<br />
flux of the wavegui<strong>de</strong> at 10.6 µm. X axis in pixels. From Labadie et al., 2005, A&A, in press.<br />
Spectro-Polarimetric Interferometry To address the promising issue of obtaining spectro-polarimetry at<br />
the milliarcsecond angular resolution, we have been involved both in the theoretical mo<strong>de</strong>lling of the interferometric<br />
observables in polarized light, and in commissioning the polarimetric mo<strong>de</strong> of the French GI2T/REGAIN<br />
interferometer (Rousselet-Perraut et al., 2005, A&A, submitted). Mo<strong>de</strong>lling the effect of instrumental polarization<br />
on interferometric performances allows us to propose some recommendations for the VITRUV concept<br />
(Sect. 11.2.3). K. Perraut (responsible) and J.B. Le Bouquin (PhD) are concerned.<br />
Data processing Mainly within the AMBER project, but also within the VITRUV and DARWIN/PEGASE<br />
studies, we have <strong>de</strong>veloped an expertise in interferometric data processing and in particular in single mo<strong>de</strong><br />
interferometry (Tatulli et al., 2004, A&A, 418, 1179). We have <strong>de</strong>veloped a new algorithm to reduce AMBER<br />
data (Millour et al., 2004, SPIE, 5491, 1222), but also other types of multi-axial data, using linear algebra<br />
and generalizing the so-called ABCD algorithm. We have investigated the sources of biases due to atmospheric<br />
jitter and the limits of the instruments in terms of field of view. This work has been mainly the work of PhD<br />
stu<strong>de</strong>nts P. Mège, E. Tatulli, J.-B. Le Bouquin and F. Millour un<strong>de</strong>r the supervision of A. Chelli, F. Malbet<br />
and G. Duvert.<br />
11.2.5 JMMC and European Interferometry Initiative<br />
The Jean-Marie Mariotti Center (JMMC) is an Expertise Center in Optical Interferometry, aiming at coordinating<br />
the French efforts in high angular resolution. Initiated by LAOG and OCA in collaboration with a dozen<br />
of other French laboratories, the JMMC has installed its coordination center at LAOG, where a project team<br />
produces the “software instruments” nee<strong>de</strong>d in data reduction and analysis tools and in preparation software for<br />
the new interferometric <strong>de</strong>velopments, especially for the VLTI. The contribution of LAOG has mainly consisted<br />
in providing the software ASPRO to prepare interferometric observations. This software is originating from the<br />
GILDAS suite where software has been <strong>de</strong>veloped for the radio interferometry at IRAM. The responsible for this<br />
software is G. Duvert. A java-based interface has also been <strong>de</strong>veloped for an easy use by external astronomers.<br />
This software has been complemented by the search of calibrators (searchCalib). ASPRO became the first<br />
virtual observatory tool, since it searches the CDS catalogs to retrieve the information required to select good<br />
interferometric calibrators. The software is adapted every semester to the new VLTI configuration provi<strong>de</strong>d by<br />
ESO. Another task of LAOG staff is to provi<strong>de</strong> support to JMMC users and is recognized as a CNAP duty.<br />
There is a strong connection between the persons working on the projects or on the R&D and the ones<br />
involved in JMMC. Some of them are in<strong>de</strong>ed taking part to both activities.<br />
This activity has naturally been exten<strong>de</strong>d at the European level where several members of our laboratory<br />
125
have taken responsibilities: A. Chelli (EII board, Coordinator of JRA4), G. Duvert (PI of a JRA4 workpackage),<br />
P. Kern (OPTICON board), C. Perrier (EII science council), G. Zins (project manager of a JRA4<br />
work-package). The JMMC and EII activities are <strong>de</strong>veloped in a separated chapter in this report.<br />
11.3 Cameras and <strong>de</strong>tectors<br />
11.3.1 Towards wi<strong>de</strong>-field cameras: WIRCam<br />
WIRCam (Wi<strong>de</strong>-field InfraRed Camera) is the second instrument of the Wi<strong>de</strong> Field Imaging Plan of the Canada<br />
France Hawaii Telescope (CFHT), providing a 20.5 × 20.5 arcminute field of view in the infrared ([0.9 µm; 2.4<br />
µm]), and completes in the infrared the MegaCam instrument operational on the CFHT since January 2003.<br />
The LAOG, un<strong>de</strong>r the lead of the local project manager E. Stadler, was responsible of the cryovessel <strong>de</strong>sign and<br />
manufacturing, including the filter wheels <strong>de</strong>sign and control/command. The LAOG was also responsible of the<br />
cryogenic system <strong>de</strong>sign, manufacturing and testing and of the temperature regulation (optics and <strong>de</strong>tectors)<br />
as well. The optics was <strong>de</strong>veloped by the University of Montreal and the <strong>de</strong>tectors control was performed by<br />
the CFHT.<br />
A challenging thermal <strong>de</strong>sign. This innovative instrument is based on four Hawaii 2RG <strong>de</strong>tectors arrays<br />
<strong>de</strong>veloped by Rockwell in a close buttable package. This camera is <strong>de</strong>signed to be placed on the prime focus<br />
of the 3.6 m CFHT telescope to take benefit of the simpler opto/mechanical <strong>de</strong>sign for a wi<strong>de</strong>-field camera.<br />
It uses a Gifford Mac-Mahon closed-cycle cryo-cooler to avoid strenuous daily re-fillings on the telescope due<br />
to poor accessibility. An optimal thermo-mechanical <strong>de</strong>sign has been <strong>de</strong>fined to meet the stringent stability<br />
requirements with minimal thermal losses. To provi<strong>de</strong> excess cooling power was not possible due to weight<br />
constraint on the camera of 250 kg. As the cryo-cooler must be easily dismounted for maintenance operation,<br />
the cooling power is transmitted by a system of two cones fitted together, one male and one female, ma<strong>de</strong> of<br />
OFHC copper and having exactly the same shape. The thermal link between the two cones is enhanced by using<br />
ultra-high vacuum grease. A tunable load between the two cones is applied by a system of titanium springs.<br />
All the cold structure is attached to the warm part of the cryostat by ten G12 composite twin bla<strong>de</strong>s.<br />
Thermal-mechanical mo<strong>de</strong>lling. In the past <strong>de</strong>ca<strong>de</strong>, new computing tools have been offered to the system<br />
<strong>de</strong>signers in terms of thermal and mechanical mo<strong>de</strong>ling. In addition to an overwhelming increase of computer<br />
capabilities, these tools are now mature enough to drive the <strong>de</strong>sign of complex astronomical instruments, in<br />
particular if these instruments have to be cooled. This allows to better un<strong>de</strong>rstand the cryogenic performances,<br />
which is a huge advantage in a new <strong>de</strong>sign approach, and to waste time during the instrument integration.<br />
A complete thermal-mechanical mo<strong>de</strong>l of the camera using Finite-Element Analysis (FEA) un<strong>de</strong>r the I-<strong>de</strong>as<br />
software was carried out. The capabilities of the I-<strong>de</strong>as thermal module (TMG) was <strong>de</strong>monstrated for our<br />
particular application 5 : studies inclu<strong>de</strong>d conduction, radiation and free-convection management, variations of<br />
the cooling power and thermal characteristics of the materials as a function of the temperature, and studies in<br />
permanent regime and transient analysis (Figure 11.10).<br />
The WIRCam cryovessel was successfully installed on the CFHT telescope by December 2004 with a team<br />
of LAOG people and has obtained its first light in March 2005 after the optics and <strong>de</strong>tector integration (Figure<br />
11.9). A temperature regulation of the <strong>de</strong>tector at the 0.002 K level was obtained on the telescope at the<br />
nominal <strong>de</strong>tector temperature of 81 K.<br />
11.3.2 Research and <strong>de</strong>velopment activities in photon counting superconducting<br />
<strong>de</strong>tectors<br />
Superconducting Tunnel Junctions (STJ) Superconducting Tunnel Junctions have been <strong>de</strong>veloped as<br />
photon counting <strong>de</strong>tectors for a wi<strong>de</strong> range of applications since they are energy resolving photon counters and<br />
5 P. Feautrier; E. Stadler; P. Puget; 2004 ; Interest of thermal and mechanical mo<strong>de</strong>ling for cooled astronomical instruments:<br />
the example of WIRCam, SPIE Proc., 5497, 149-160<br />
126
Figure 11.9: Left View of the WIRCam cryovessel during its installation on the CFHT (March 2005). Right:<br />
raw data (no flat-fielding) from an engineering test J band image of the M17 nebula obtained in 30 s with a seeing<br />
of 0.4 arcsec. The quadrants show the 4 <strong>de</strong>tector array and the gap in between. The excellent cosmetic quality<br />
can be judged from the zoom below. Bottom: zoom of the previous image, raw data without flat-fielding,<br />
showing the amazing cosmetic quality of the last Rockwell infrared <strong>de</strong>tectors.<br />
can be used from the infrared (2 µm) to X-ray wavelengths with good quantum efficiency (60%) 6 . The aim<br />
of our work was to investigate the interest of this kind of <strong>de</strong>tectors for ground based low-light astronomical<br />
applications and compare them to Superconducting Single Photon Detectors (SSPD) (see next paragraph).<br />
Since the conventional <strong>de</strong>tector arrays based on semi-conductor <strong>de</strong>vices have recently progressed toward photon<br />
counting <strong>de</strong>tectors in the visible 7 , some niches have to be found for this type of <strong>de</strong>tectors where conventional<br />
<strong>de</strong>vices cannot compete. The astronomical applications that could be investigated are wave-front sensing <strong>de</strong>tectors<br />
for adaptive optic systems, fringe sensors and focal plane instruments for interferometry in the near<br />
infrared. This work has been carried out in a collaboration between three laboratories from <strong>Grenoble</strong>: the<br />
LAOG (responsible of the activity un<strong>de</strong>r the lead of P. Feautrier), the CRTBT(un<strong>de</strong>r the lead of A. Benoit),<br />
and the CEA-<strong>Grenoble</strong>/DRFMC/LCP (un<strong>de</strong>r the lead of Jean-Clau<strong>de</strong> Villégier) in charge of the <strong>de</strong>vice fabrication<br />
(Figure 11.11).<br />
At the end of the last LAOG PhD thesis based on this subject, we <strong>de</strong>ci<strong>de</strong>d to put our efforts on some slightly<br />
different superconducting <strong>de</strong>tectors, the SSPD (see next paragraph), which present important advantages compared<br />
to STJ:<br />
6 G. Brammertz, A. Peacock, P. Verhoeve, D.D.E. Martin, and R. Venn, Optical photon <strong>de</strong>tection in Al superconducting tunnel<br />
junctions, Nucl. Inst. and Meth. A, 520, 508 (2004)<br />
7 C. D. Mackay, R. N. Tubbs, R. Bell, D. J. Burt, P. Jerram, and I. Moody, Sub-electron read-out noise at MHz pixel rates, Proc.<br />
SPIE, 4306, 289 (2001)<br />
127
Figure 11.10: thermal mo<strong>de</strong>ling of WIRCam using FEA analysis and the I<strong>de</strong>as/TMG thermal mo<strong>de</strong>lling<br />
software. Left: thermal mo<strong>de</strong>l in the steady state of the filter wheels cage and the optical barrel; right:<br />
thermal mo<strong>de</strong>l of the cold finger which transmits the cryogenic power to the cold structure.<br />
• Devices simpler to manufacture, low cost (one single active layer)<br />
• Far higher speed (1 GHz instead of 10 kHz)<br />
• Developments supported by numerous practical applications, including commercial ones, contrary to STJ.<br />
Superconducting Single Photon Detectors (SSPD) Niobium Nitri<strong>de</strong> (NbN) Superconducting Single-<br />
Photon Devices are sensitive to radiation from UV to mid-IR. In terms of speed and sensitivity, they outperform<br />
any semiconductor and superconducting photon counters. They reach Quantum Efficiency (QE) of 20-30% at<br />
wavelengths of [1.3 µm; 1.55 µm], related to intrinsic QE close to 100%. Dark counting rate is extremely<br />
low: 10 −4 counts per second and less. Measured Noise Equivalent Power (NEP) is about 5.10 −21 W/ √ Hz in<br />
a wavelength range of [0.5 µm; 1.5 µm]. NbN SSPD is practical <strong>de</strong>vices for non-invasive optical analysis of<br />
CMOS circuits and can be successfully used for quantum communications and quantum cryptography. These<br />
new <strong>de</strong>tectors are <strong>de</strong>veloped in a collaboration with the CEA <strong>Grenoble</strong> and the <strong>Laboratoire</strong> <strong>de</strong> Spectrométrie<br />
Physique <strong>de</strong> <strong>Grenoble</strong>. Some first <strong>de</strong>vices have been recently produced (Figure 11.11) and are currently un<strong>de</strong>r<br />
performance evaluation. These <strong>de</strong>tectors are particularly interesting for the Lippmann spectral <strong>de</strong>tectors (see<br />
Prospective).<br />
Figure 11.11: Left: 3x3 pixel array of 30 µm x 30 µm Ta-based STJ’s. Upper middle: <strong>de</strong>tails of the<br />
array structure with a Scanning Electron Microscope (SEM). Lower middle: single Ta-STJ. Right Scanning<br />
Electron Microscope (SEM) photography of a SSPD mean<strong>de</strong>r fabricated at the CEA-<strong>Grenoble</strong>. The width of<br />
the stripes and the distance between them are 150 nm. Courtesy of CEA-<strong>Grenoble</strong>/DRFMC/LCP (Jean-Clau<strong>de</strong><br />
Villégier).<br />
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Chapter 12<br />
Perspectives<br />
The instrumental research and <strong>de</strong>velopment objectives of GRIL are <strong>de</strong>scribed here using the same frame as for the<br />
results, distinguishing between three instrumental families. The R&D activities and instrumental realizations,<br />
although tightly linked as previously explained, are separately <strong>de</strong>scribed only for sake of clarity.<br />
12.1 Adaptive optics<br />
We <strong>de</strong>scribe below the projects that are proposed for the next ”quadrennial period”. The instruments come<br />
first since there are the ultimate goal of GRIL activities. R&D is exposed afterward. Part of the projects<br />
have already started and other are extension of previous works into a more advanced and/or more ambitious<br />
phase. From the priority already exposed, the future activities will be preferentially directed towards extreme<br />
AO systems <strong>de</strong>velopment.<br />
12.1.1 Instruments<br />
PRIORITIES<br />
The imminent VLT PF 2 nd generation instrument whose contract should be signed early 2006, implies<br />
an important commitment on behalf of the LAOG with an expected schedule of the commissioning in 2010-2011,<br />
i.e. after the end of the present prospective period. See the chapter 11.1.2 for the scope of this instrument.<br />
LAOG provi<strong>de</strong>s some of the key-persons of the project and a large part of the resources for the integration and<br />
test phase. This project is therefore a major un<strong>de</strong>rtaking for our laboratory with two crucial expected returns :<br />
on the scientific si<strong>de</strong>, a leading role in the survey, and on the technical aspects, an additional expertise that will<br />
be essential for the extreme AO-based instrumentation of the ELT era.<br />
Studies for ELT The preparation of ELTs already require conceptual studies both on the <strong>de</strong>dicated AO<br />
systems and the instruments based on special optimization of these systems. Among the projected concepts,<br />
an extreme AO-based imager, EPICS, takes benefit of the advances that led to the conceptual <strong>de</strong>finition of the<br />
VLT-PF, to reach the ultimate contrast for e.g. low-mass extra-solar planet search. A very preliminary study<br />
of this concept has started with a participation of LAOG and shows the potential interest of a 3D spectroscopic<br />
approach as we previously <strong>de</strong>monstrated with the GRaF and GRiF instruments. We wish to keep involved in<br />
the next phases and specially the optimization of this ambitious instrument.<br />
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Figure 12.1: All the GRIL projects for the next 5 years. Those yet to be <strong>de</strong>ci<strong>de</strong>d are indicated as ”un<strong>de</strong>r<br />
discussion”. Note that GRIL will not get involved in all of them (see text). See also caption of Figure 10.1<br />
OPTIONAL PROJECTS<br />
Following the opportunities that will appear in the next years, the LAOG could participate in the projects<br />
presented below <strong>de</strong>pending on the conditions and possibilities.<br />
Interferometric telescopes AO equipment Equipping with AO systems the small telescopes used, for<br />
instance, in large interferometers is in discussion. Observations with the VLTI AT would benefit from it and a<br />
similar need is invoqued for CHARA. These needs may be covered by low-cost AO systems that are still to be<br />
<strong>de</strong>signed. In the event where the LAOG would start a full AO system <strong>de</strong>velopment, we would establish a link<br />
with these partners in or<strong>de</strong>r to try collaborating on this matter.<br />
AO equipment for ELT Another direction in the longer range is a participation to the AO equipment<br />
of ELT by providing micro-mirrors components and possibly other sub-systems of these probably large and<br />
complex systems. AO might be employed here not only for turbulence-<strong>de</strong>gra<strong>de</strong>d PSF correction but also for<br />
instrumental phase errors correction. Our involvement will largely <strong>de</strong>pend on the success of R&D planned in<br />
the JRA1 and on the conceptual view emerging from the starting studies.<br />
130
12.1.2 R&D activities<br />
PRIORITIES<br />
Forthcoming <strong>de</strong>formable mirrors <strong>de</strong>velopments in the frame of the FP6 Opticon JRA1. The main goal<br />
is to make technological <strong>de</strong>velopments aiming at better performances of micro-mirrors in term of number of<br />
actuators, stroke accuracy and other relevant characteristics for astronomical instrumentation of large telescopes<br />
(including ELTs). A secondary objective is to <strong>de</strong>velop a low-cost product to <strong>de</strong>crease the total cost of systems<br />
for intermediate size telescopes or special applications (multi-objects FALCON approach or ophthalmological<br />
applications for instance).<br />
This objective should be mainly managed in the frame of the JRA1 network, with possible support coming from<br />
other sources and/or contracts (ANR, RNTS, etc.). But, in view of the potentially complex tasks to achieve,<br />
it is expected that a continuation within the PF7 will be necessary. In this event, LAOG is to be a natural<br />
partner to this future networking phase.<br />
Toward system <strong>de</strong>velopment With the advent of small and comparatively low-cost <strong>de</strong>formable mirrors,<br />
producing full AO systems for other applications than the large telescopes only becomes possible. A very useful<br />
application directly related to our interferometric needs is to be found in systems <strong>de</strong>dicated to auxiliary<br />
telescopes (of large interferometers such as VLTI or CHARA). This requires the <strong>de</strong>velopment of whole systems<br />
more adapted to this new configuration. We intend to proceed to such system studies and find partners to<br />
help us provi<strong>de</strong> more ready-to-use AO systems, by contributing for instance to the wavefront sensing <strong>de</strong>vices,<br />
the real-time calculators and the related control software. In this context, LAOG could be involved in the<br />
<strong>de</strong>velopment of a large part of such systems.<br />
12.1.3 Means and methods<br />
Networking Because of the large place that AO is likely going to take in the future TGE, it seems to us<br />
quite essential to increase the expertise in the components, control and system aspects of AO systems in France,<br />
presently mostly present at ONERA. LAOG can participate to this effort by bringing what is most specific to<br />
<strong>Grenoble</strong> notably in system <strong>de</strong>sign capabilities, component <strong>de</strong>velopment know-how, fruitful connection to local<br />
micro-electronics institutes. This requires to increase our capabilities, mostly absorbed by VLT-PF, to a higher<br />
level than now in or<strong>de</strong>r to be able to participate in the nation-wi<strong>de</strong> effort besi<strong>de</strong> the current operations in Paris<br />
and Marseille. This would imply a substantial evolution in <strong>de</strong>dicated manpower, funding and room access (this<br />
is discussed in part I).<br />
For the same reasons, it is naturally inten<strong>de</strong>d to be present in the <strong>de</strong>finition of programmes and tasks for the<br />
FP7, starting in 2009. If we can increase our AO capabilities in <strong>Grenoble</strong>, our implication could be larger with<br />
more responsibilities taken by the laboratory than presently.<br />
Industrial <strong>de</strong>velopment Following the <strong>de</strong>velopment agreements related to the production and selling tasks<br />
of MMD un<strong>de</strong>r contract with FLORALIS (a subsidiary of UJF) and Imagine Eyes (see 11.1.3, we intend to<br />
keep this scheme in the near future with a prospect of several MMD produced per year as a start and likely<br />
other productions <strong>de</strong>rived from our other R&D activities.<br />
Manpower The VLT-PF realization will be a limiting factor of our other activities during the next ”quadrennial<br />
contract”. In or<strong>de</strong>r to cope with our other projects, especially the R&D ones, the LAOG must get<br />
reinforced in some vital functions in the short term. The needs are three-fold :<br />
- system engineering capabilities with proven project management experience, calling for a high-level specialist<br />
of AO systems ;<br />
- instrumental software <strong>de</strong>velopment support; - thesis direction capabilities oriented toward AO system concept<br />
and control, calling for a habilitated researcher or research engineer.<br />
Moreover subtantially increasing our global capabilities in AO will require more positions at a senior level and<br />
at least one post-doctoral position during the period.<br />
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12.2 Optical interferometry<br />
As for adaptive optics, part of the projects, as proposed below, have already started in the current ”quadrennial<br />
contract” or are extension of previous works into a more advanced phase. From our priorities <strong>de</strong>scribed before,<br />
they will be preferentially directed towards imaging interferometry and nulling interferometry, taking benefit<br />
from the integrated optics advances in which LAOG has taken a large part.<br />
12.2.1 Instruments<br />
PRIORITIES<br />
Imaging interferometry In some years, optical interferometry routine imaging will be one of the major<br />
achievements in astronomical instrumentation. The LAOG is strongly promoting this view and therefore is<br />
making steps towards this accomplishment.<br />
• VITRUV for the VLTI The LAOG has <strong>de</strong>veloped a proposition for a second generation VLTI instrument,<br />
VITRUV, that is aimed at imaging with 4 at start, 8 at maximum, telescopes offering a huge improvement<br />
in the u,v-plane coverage over AMBER. Its concepts takes benefit from the experience acquired with the<br />
tests of IONIC on IOTA and VLTI and is precisely oriented toward the main priority of ESO known as<br />
the ”4x4 VLTI box” that calls for 4 or more recombined telescopes, with phase reference allowing true<br />
imaging on faint sources. The project has passed a pre-phase A study and has been proposed to ESO<br />
in April 2005 (see section 11.2.3). Since then, the LAOG is implicitly committed to VITRUV in terms<br />
of key-responsabilities, <strong>de</strong>sign, integration, tests and commissioning and is awaiting the ESO <strong>de</strong>cision to<br />
start the phase-A study. As AMBER was, this project would be an international collaboration. Several<br />
European partners have expressed their interest in participating to the project at various levels. It must<br />
be noted that, due to its concept, VITRUV should require slightly less resources than AMBER.<br />
• CHARA : participation to the instrumentation In the path to VITRUV, we have <strong>de</strong>veloped strong ties<br />
with Pr. Monnier at U. of Michigan in or<strong>de</strong>r to test key VITRUV building blocks on a real on-sky<br />
imaging experiment. The MIRC imaging instrument of CHARA is fully compatible with LAOG integrated<br />
optics beam combiners and offers a unique opportunity to <strong>de</strong>monstrate VITRUV imaging capability. The<br />
eventuality to leave useful components for inclusion in a CHARA general-User instrument such as MIRC<br />
is an open question.<br />
OPTIONAL PROJECTS<br />
The following projects are either space projects or <strong>de</strong>dicated to Antarctica. Because of our available resources,<br />
the LAOG contribution can only be kept limited if VITRUV is launched as we do hope. But if it was not, our<br />
contribution could probably be increased since our interest in these projects is important.<br />
• PEGASE and/or DARWIN space missions LAOG is directly involved in the PEGASE project which was<br />
presented at the French CNES space agency as an answer to the Call-for-proposal for a free-flyers mission<br />
and is now a candidate for a Phase A study. At this stage, LAOG contributes to the scientific drivers<br />
<strong>de</strong>finition (study of gaps in protoplanetary disks and spectroscopic characterization of hot Jupiters).<br />
Later on, LAOG could have a technical participation in the global conceptual <strong>de</strong>sign and the recombining<br />
aspects if IO is retained as a solution. The involvement in PEGASE is not only motivated by standalone<br />
objectives but also by the will to participate to the very challenging mission DARWIN that we have been<br />
preparing by several R&D related to DARWIN (see Sect. 11.2.4), un<strong>de</strong>r ESA contracts. In the event where<br />
PEGASE were not selected for a phase-A study, our involvement in the R&D preparation to DARWIN<br />
would however be maintained because of the needs for a long-term approach to this most challenging<br />
mission.<br />
• Antarctica Genie-type projects Mark Swain (from JPL) spent one year in LAOG to work on exploitation<br />
of AMBER and Antarctic interferometry. On this last subject, the LAOG has helped him to present the<br />
problematics of Antarctic interferometry throughout Europe. Also thanks to the fruitful links between the<br />
132
laboratories of OSUG, a collaboration has grown up between LAOG and LGGE (H. Gallee) on the climate<br />
mo<strong>de</strong>lling in Antarctica to mo<strong>de</strong>l astronomical seeing, <strong>de</strong>monstrating the importance of the boundary layer<br />
in Antarctica, of the or<strong>de</strong>r of 20-30 m high. The result is that seeing above this layer is exceptionally good<br />
almost like space conditions, but at the ground level it is rather similar to other sites. Work has started<br />
to use these results to predict performances of future instruments in Antarctica thanks to the experience<br />
<strong>de</strong>veloped at LAOG for the AMBER instrument. Preparatory activities in view of astronomical use of the<br />
Dome C Site in Antarctica have been largely reinforced early 2005 with various medium-size equipment<br />
funding requests (to INSU/CSA and/or to IPEV) by several French laboratories and a European FP6<br />
funding request led by N. Epchtein (LUAN), aiming at promoting first level studies of astronomical use<br />
of the Dome C, whose funding would cover the period 2006-2007 and whose rationale must also be found<br />
in the preparation of a large scale FP7 proposal.<br />
In this context, LAOG is involved in the FP6 request at a limited level (6 men-months with 4 involved<br />
persons) with the aim to participate in the <strong>de</strong>finition of the astronomical goals and the studies of the<br />
instrumental optimization for the Antarctica environment. We intend in particular to bring our expertise<br />
in integrated optics interferometric recombiners and in interferometry at a system level.<br />
In parallel, the LAOG may wish to look into the potentially major interest that GENIE, or an other<br />
nulling instrument like ALLADIN, be installed at Dome C rather than on the VLTI and the compared<br />
figures of merit to install 8m-type telescopes at Dome C as an alternative to ELTs on standard sites. We<br />
intend to participate in the conceptual studies on which future <strong>de</strong>cisions will have to be based.<br />
12.2.2 Software <strong>de</strong>velopment for interferometry<br />
JMMC and European networks The <strong>de</strong>tailed objectives of JMMC for this period will be <strong>de</strong>scribed in<br />
the report and request for renewal that will be prepared by the JMMC as a CNRS GdR (their preliminary<br />
presentation is given in Appendix 2). We <strong>de</strong>scribe here how we feel, at LAOG, the orientation of the JMMC<br />
should be for the next years.<br />
The JMMC is currently heavily loa<strong>de</strong>d by the tasks assigned by its council to which its participation, as a<br />
major actor, to the Opticon JRA4 has ad<strong>de</strong>d further pressure in 2004. Its present main gui<strong>de</strong>line is to <strong>de</strong>velop<br />
software for the end Users of interferometry. The scheduled tasks inclu<strong>de</strong> the <strong>de</strong>velopment of software specific<br />
to the optimized use of AMBER and it can be anticipated that the JMMC will try to cover the new needs<br />
induced by the forthcoming installation of VITRUV-type (i.e. imagers) instruments on the VLTI. Moreover,<br />
optical interferometry already joined other observational techniques in the more general framework of virtual<br />
astronomical observatories, bringing some more constraints to the work load of JMMC.<br />
In the future, the <strong>de</strong>velopment of JMMC should be pursued with in mind an easy access to interferometric data<br />
by the general astronomers both for preparing observations and for reducing them or access to science archives.<br />
In this respect, a major outcome of JMMC is the possibility to produce and offer an image reconstruction<br />
software optimized for aperture synthesis by optical interferometry. With all these un<strong>de</strong>rtakings, the JMMC is<br />
very likely to be continued by CNRS for at least the length of the new ”quadrennial contract”.<br />
In the longer term, it must be ad<strong>de</strong>d that it could be beneficial to the community that the JMMC extend its<br />
activities (services and support) to the larger domain of all high angular resolution techniques i.e. including the<br />
specific AO data expected with ELTs.<br />
12.2.3 R&D activities<br />
PRIORITIES<br />
Advanced IO components <strong>de</strong>velopment In the domain of near-IR IO, the basic recombining functionalities<br />
are now rather well mastered at least for 3 telescopes recombination. Future progress will come from<br />
more functionally complex components, i.e. allowing recombination of more than 3 beams, or providing not yet<br />
integrated functions like fringe tracking, achromatic phase shift or active functions (e.g. OPD scanning). Such<br />
components would further strengthen the advantages of IO-based interferometric benches, therefore <strong>de</strong>crease<br />
the overall system costs, a particularly interesting prospect for space applications.<br />
As we did before with IOTA, we intend to test the components previously characterized in the laboratory on<br />
the CHARA interferometer (Georgia State University) whose size and access are more adapted to this goal than<br />
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the VLTI. CHARA is equipped with an imaging instrument, MIRC, fully compatible with LAOG integrated<br />
optics beam combiners, which produced its first results in september 2005.<br />
Extension to thermal IR Extension of current or programmed instruments such as VITRUV (see Section<br />
12.2.1) to the medium-infrared (2 to 5 µm) is scientifically attractive. As such, this goal motivates R&D<br />
activities aimed at <strong>de</strong>veloping IO components adapted to this wavelength range.<br />
The ESA-fun<strong>de</strong>d contractual work IODA for <strong>de</strong>velopment and characterization of IO components optimized<br />
for the thermal IR (the range of interest for DARWIN), in collaboration with LETI/CEA and ALCATEL has<br />
provi<strong>de</strong>d several potentially useful technological solutions. One of the key feature is to maintain the leakage<br />
level to the very low level imposed by the DARWIN requirements. We now intend to continue this <strong>de</strong>velopment<br />
with the same partners in view of promoting an IO concept for the DARWIN nulling. LAOG would essentially<br />
keep the same role (high level requirements <strong>de</strong>finition and components characterization) with a possible<br />
strengthening of the test phase on a nulling bench in the lab (which could be that of IAS).<br />
MORE AMBITIOUS PROJECTS<br />
Towards visible wavelengths ? A more open question is that of an evolution toward the wi<strong>de</strong>ly <strong>de</strong>sired<br />
visible domain. Current limitations of the optical interferometers (absence of AO correction in V for instance)<br />
has preclu<strong>de</strong>d ambitious moves into this direction and interferometry in the visible has remained limited to a few<br />
experiences (REGAIN in France) operating generally in multi-mo<strong>de</strong>s. Because of the expected progress in AO<br />
systems mentioned before and the technological possibilities, it seems reasonable to <strong>de</strong>fend that using IO toward<br />
the visible on a AO-corrected interferometer can now be projected in the new future. We may participate to<br />
this evolution when a system study confirms that conditions are met.<br />
ELT pupil masking and reconfiguration ? Through pupil masking and reconfiguration, diffraction-limited<br />
resolution in V on a ELT may become possible before any AO system can be ma<strong>de</strong> operational, if ever. This<br />
approach relies on the use of gui<strong>de</strong>d optics for the sub-pupils reconfiguration. A possible participation to such<br />
a project un<strong>de</strong>rtaken at LESIA, could benefit from our simultaneous expertise in adaptive optics systems and<br />
interferometric concepts at a system level. Our involvement will strongly <strong>de</strong>pend on, obviously, the actual<br />
collaboration possibilities and on the realism of access to an ELT for this particular science goal, at least during<br />
the building phase of the primary mirror.<br />
12.2.4 Means and methods<br />
Manpower The IODA project lacks some resources that should be compensated by recruiting at a postdoctoral<br />
level and also at a permanent position (a possibility being the University position opened in 2006). In<br />
the mid-term, a technical position with a technological profile is necessary. The general needs for exploiting<br />
imaging capabilities of VITRUV should be covered by a research position.<br />
Locally, an increase of resources of the JMMC center of coordination will be necessary to fulfill its role within<br />
the JMMC network of participating laboratories. The actual need, that <strong>de</strong>pends not only on LAOG involvement<br />
but of the whole network, is exposed in the JMMC report.<br />
12.3 Cameras and <strong>de</strong>tectors<br />
Towards the ultimate photon <strong>de</strong>tection, GRIL maintains a high level knowledge of photon <strong>de</strong>tection (milimetric<br />
wave bolometers, NIR and Visible) coupled or not to spectroscopy. The LAOG will continue to maintain an<br />
expertise in this domain contributing to the R&D and the <strong>de</strong>finition of <strong>de</strong>tectors used by astronomy.<br />
It is un<strong>de</strong>rstandable that the astronomy community cannot afford to make alone the R&D effort necessary to<br />
progress in this matter. For this reason, GRIL takes benefit of the growing expertise in micro and nanotechnologies<br />
in the site of <strong>Grenoble</strong> at large (e.g. with CEA, CNRS and INPG laboratories) to build <strong>de</strong>dicated<br />
134
collaborations. Moreover, part of our work in this field is done within large networks such as ANR-fun<strong>de</strong>d or<br />
OPTICON JRA collaborations.<br />
12.3.1 Instrument support technology<br />
Fast <strong>de</strong>tectors for wavefront sensing: the JRA2 of Opticon Visible <strong>de</strong>tectors fully matching the<br />
requirements of Adaptive Optics wavefront sensors for 10-m class telescopes do not yet exist: current <strong>de</strong>tectors<br />
have frame rates which are too slow and which are too noisy for the second generation of AO systems. The<br />
visible <strong>de</strong>tectors <strong>de</strong>veloped by the JRA2 will be <strong>de</strong>dicated to AO applications. The scalability of these <strong>de</strong>tectors<br />
for ELT AO systems will be taken into account. The participants will attempt to <strong>de</strong>fine, manufacture and fully<br />
characterize the best possible <strong>de</strong>tector working at visible wavelengths which is suitable for wavefront sensors in<br />
Adaptive Optics (AO) systems. This Joint Research Activity is closely linked to the Opticon JRA1-Adaptive<br />
Optics. This will ensure that this <strong>de</strong>tector <strong>de</strong>velopment follows the AO requirements in terms of wavefront<br />
sensing <strong>de</strong>tectors. The <strong>de</strong>tector format will be 240x240 pixels, the frame rate will be very fast (up to 2 kHz)<br />
while the readout noise will be kept extremely low (typically below 1 e − ) by using the Electron Multiplying<br />
technique <strong>de</strong>veloped by e2v Technologies, known as L3Vision. The following list of tasks concerns the LAOG<br />
participation to theJRA2:<br />
• Responsibility of the JRA: management of the activity, general meetings, report to the European Community,<br />
reports and Opticon meetings.<br />
• Responsibility of the cryogenic system: mechanical <strong>de</strong>sign of the cold head, cryogenic <strong>de</strong>sign, thermal<br />
mo<strong>de</strong>ling of the whole camera, integration and cryogenic tests.<br />
The OPTICON JRA2 being scheduled for 4 years, should continue during the next ”quadrennial contract”,<br />
implying some continuing responsibility especially at the direction of the JRA2. As for AO components <strong>de</strong>velopment,<br />
this programme is likely to be proposed for a continuation during FP7. LAOG will have, in the two<br />
next years, to express its will to keep involved in the organization of such a network and in its actual role herein.<br />
The present day role came from the experience acquired with the NAOS visible wavefront sensor and anterior<br />
expertise in different types of <strong>de</strong>tectors (thermal IR, near IR and supraconducting <strong>de</strong>vices). LAOG wishes to<br />
keep this expertise and/or <strong>de</strong>velop it further.<br />
12.3.2 R&D activities<br />
The future: a Lippmann spectral <strong>de</strong>tector ? Following to the Lippmann color photography invention at<br />
the end of the 19th century, we propose to renew the i<strong>de</strong>a of stationary waves <strong>de</strong>tection in the third dimension.<br />
Until now, using electronic <strong>de</strong>tectors rather than photographic emulsions was not possible because of their<br />
too large size compared to the dimension required by standing waves sampling, typically one fourth of the<br />
wavelength (i.e. about 100 nm for visible light). Recently E. le Coarer has proposed to perform this <strong>de</strong>tection<br />
in the evanescent field of optical wavegui<strong>de</strong>s using superconducting <strong>de</strong>tectors (SSPD) <strong>de</strong>veloped by the CEA-<br />
<strong>Grenoble</strong>/DRFMC. If successful, this still very prospective <strong>de</strong>velopment would pave the way for a new generation<br />
of ultra small spectrographs that should still have the same efficiency as all other spectral systems known<br />
until now. It would also allow to build spectrograph mosaics rather than bulky 3D spectrographs that are<br />
conventionally <strong>de</strong>veloped.<br />
Detectors of this kind would have numerous applications in all fields where very fast spectroscopy is required like<br />
telecommunications, cryptography and medicine. This is the reason why UJF has taken a patent on this topic.<br />
In mid-2006, the studies that already started will show whether the <strong>de</strong>velopment can be further un<strong>de</strong>rtaken.<br />
LAOG will then have to analyze which objective is realistic and to <strong>de</strong>ci<strong>de</strong> what actual effort can be invested<br />
into this direction.<br />
12.3.3 Means and methods<br />
The need for rather large collaborations is especially true for the Lippmann <strong>de</strong>tector <strong>de</strong>velopment. In the<br />
continuity with successful collaborations with CEA-DRFMC, CRTBT, IMEP and IRAM, and in the context of<br />
the MINALOGIC facilities, at least two new emerging collaborations can be cited to this end:<br />
135
• ANR Alter<strong>de</strong>tect, with IMEP : simultaneous <strong>de</strong>monstration of Lippmann spectroscopic capability using<br />
Radio then millimetric waves and Near Infrared gui<strong>de</strong>d optics.<br />
• ANR Nano<strong>de</strong>sir, with CEA-DRFMC : The Lippmann effect coupled supraconducting SSPD to generate<br />
a nanosystem achieving photon counting and spectroscopy is one driver to <strong>de</strong>velop research on superconductivity.<br />
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Chapter 13<br />
Recruitment plan<br />
GRIL needs are two-fold: researchers with instrumental skills able to fullfill key responsabilities in large projects<br />
or with research programs in specific technological fields that are at the heart of our R&D projects; engineers with<br />
a strong motivation in R&D activities and expertise in the fields that are of importance for our <strong>de</strong>velopments.<br />
Because of the strong commitment the LAOG has towards the VLT Planet Fin<strong>de</strong>r realisation and that of<br />
the VLTI 2µm imager, very likely to be scheduled soon, it is essential to increase our resources in some very<br />
specific fields of expertise in or<strong>de</strong>r to maintain and consolidate our R&D capabilities. For this reason, during<br />
the next quadrennal period, GRIL should either recruit or welcome external persons on the various profiles<br />
<strong>de</strong>scribed below according to the two categories, pure instrumental profiles (GRIL recruitments) and mixed<br />
astrophysical-instrumental profiles (thematic team recruitement with participation to GRIL activities).<br />
GRIL profiles<br />
1. Adaptive optics R&D and system<br />
Goal: Increase the LAOG capabilities in AO instrumentation. Because of our major involvement in the<br />
large PF project, most of our capabilities connected to AO expertise will be focused on the realisation<br />
of this instrument. In or<strong>de</strong>r to succeed in this whole pursuing our innovative R&D activities in AO, we<br />
need to increase our global capabilities in AO components R&D and/or system <strong>de</strong>finition by recruiting<br />
an AO-oriented instrumentalist researcher accompaning the recruitment of an AO-<strong>de</strong>dicated project manager/system<br />
engineer (IR1). This should occur in the fall of 2006.<br />
Target: 2007 or 2008<br />
2. Nulling interferometry at thermal IR wavelengths<br />
Goal: Preparation studies for Darwin. In parallel and support to R&D on thermal IR guiding optics,<br />
such as IODA and other possible studies in preparation for DARWIN, we have i<strong>de</strong>ntified the need for<br />
a researcher strongly <strong>de</strong>dicated to the search for planets in MIR in general and personally involved in<br />
the preparation of DARWIN or precursor missions. He would have to pilot the preparatory studies that<br />
LAOG is performing and possibly going to enlarge in the frame of its pluriannual commitment to ESA<br />
and ALCATEL ALENIA partnership.<br />
Target: 2007<br />
3. JMMC support for 4-6T exploitation<br />
Goal: Participation to the JMMC <strong>de</strong>velopments supporting the VLTI evolution toward more than 3 beams.<br />
LAOG has a special role in the JMMC since it harbors the coordination center and some key members<br />
of the working groups. Because of its probable involvement in a second generation instrument, it should<br />
also help in <strong>de</strong>veloping the <strong>de</strong>dicated tools for the VLTI exploitation.<br />
Target: 2008<br />
It should be noted that these profiles might evolve according to the actual profile of the MdC who should<br />
be recruited in section 34 or any other recruitment possibly achieved in 2006.<br />
137
Mixed GRIL-other team profiles<br />
1. Adaptive optics instrumental <strong>de</strong>velopment<br />
Goal: Increase the LAOG capabilities in AO instrumentation. Because of our major involvement in the<br />
large PF project, we need to increase our capabilities of integration of AO-based instrumentation by<br />
recruiting an astrophysicist with experience in the final tests and performance analysis as well as in the<br />
operation and exploitation of AO imagers. Such a profile, with instrumentation as a secondary motivation<br />
(i<strong>de</strong>ally CNAP ”services d’observation”), should appear both in GRIL and in a thematic team.<br />
Target: 2007 or 2008<br />
2. NIR interferometric spectro-imaging<br />
Goal: Exploitation of the new imaging capabilities of the VLTI. Second generation instruments, such as<br />
VITRUV, will provi<strong>de</strong> unprece<strong>de</strong>nted imaging capabilities to the VLTI. The need is to prepare a<strong>de</strong>quately<br />
the LAOG to the optimized exploitation of this mo<strong>de</strong> by recruting a researcher directly involved in the<br />
VLTI 2nd generation instrumentation realisation. Such a profile, with instrumentation as additional<br />
competence and motivation, could appear both in GRIL and in a thematic team.<br />
Target: 2009<br />
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Chapter 14<br />
Appendix<br />
14.1 Staff<br />
14.1.1 Permanent staff<br />
People involved in the instrumental activities at LAOG over the 2001-2005 period are listed in the table 14.1<br />
below. Some members of GRIL being also active in another team, their other team is also indicated. Those<br />
mostly involved in prospective and/or publishing in instrumental research are in the upper part of the list.<br />
Other are contributors at various levels in the GRIL activities.<br />
14.1.2 PhD stu<strong>de</strong>nts<br />
• Adaptive optics projects: Gael Chauvin (NAOS), Guillaume Montagnier (VLTPF), Jean-François Sauvage<br />
(VLTPF), Wilfrid Schwartz (DM).<br />
• Interferometric projects: Myriam Benisty (IONIC, VITRUV), Carla Gil (AMBER), Pierre Haguenauer<br />
(IONIC, MAII), Oscar Hernan<strong>de</strong>z (AMBER), Lucas Labadie (IODA, IONIC), Emmanuel Laurent (IONIC,<br />
IODA), Jean-Baptiste Le Bouquin (IONIC, VITRUV), Laure Lagny (IONIC), Pierre Mège (AMBER),<br />
Florentin Millour (AMBER), Eric Tatulli (AMBER, JMMC).<br />
14.1.3 Other contributors<br />
• Adaptive optics projects: Amandine Blanc (NAOS, MCAO, 2year CDD), Rodolphe Conan (VLTPF, 3year<br />
post-doctoral fellow), Zoltan Hubert (DM, 1year CDD).<br />
• Interferometric projects: Swain Mark (API, IONIC - Visitor), Guillaume Mella (JMMC, JRA4 - CDD),<br />
Sylvain Cètre (JMMC, JRA4 - CDD), Willem-Jan <strong>de</strong> Wit (AMBER - postdoc), Emilie Herwats (VIT-<br />
RUV, PEGASE - Master 2 stu<strong>de</strong>nt), Pierre Demolon (IONIC - INSA Rennes stu<strong>de</strong>nt), Fatemeh Zabihian<br />
(IONIC-VLTI - Master Pro Optique stu<strong>de</strong>nt), Pierre Gratier (VITRUV - ENS Lyon stu<strong>de</strong>nt), Bram Acke<br />
(AMBER - external PhD stu<strong>de</strong>nt - Univ. Louvain), Frédéric Rooms (IONIC - external PhD stu<strong>de</strong>nt -<br />
IMEP), Elena Dufour (IODA - ENSI Caen), Coralie Aubert (VITRUV - Master 1 stu<strong>de</strong>nt), Laurianne<br />
Pichon (VITRUV), Axel Chetail (VITRUV), Benoit Neichel (VITRUV).<br />
14.2 Main publications<br />
• NAOS on-line characterization of turbulence parameters and adaptive optics performance, Fusco T., Rousset<br />
G., Rabaud D., Gendron E., Mouillet D., Lacombe F., Zins G., Ma<strong>de</strong>c P.-Y., Lagrange A.-M., Charton<br />
J., Rouan D., Hubin N., Ageorges N.; 2004; Journal of Optics A: Pure and Applied Optics; 6; 585-595<br />
139
Name Gra<strong>de</strong> Comm. Project<br />
Berger Jean-Philippe AA FOST IONIC, VITRUV, JMMC<br />
Beuzit Jean-Luc CR FOST MDM, VLTPF, MCAO, WIRCAM<br />
Chalabaev Almas CR FOST GRIF, VLTPF<br />
Charton Julien IR MDM, NAOS, VLTPF<br />
Chelli Alain A FOST AMBER, JMMC, EII<br />
Duvert Gilles AA FOST AMBER, JMMC, EII<br />
Feautrier Philippe IR (HDR) NAOS, WIRCAM, VLTPF<br />
Jocou Laurent AI MDM, IONIC, MAII, IODA, VITRUV<br />
Kern Pierre IR NAOS, MDM, AMBER, IONIC, MAII, IODA, VITRUV, EII<br />
Le Coarer Etienne IR (HDR) AMBER, IONIC, IODA, VITRUV<br />
Malbet Fabien CR FOST AMBER, IONIC, VITRUV, JMMC, PEGASE, EII<br />
Perraut Karine AA AMBER, IONIC, IODA, VITRUV<br />
Perrier Christian A FOST AMBER, MAII, VITRUV, EII, NACO, VLTPF, WIRCAM<br />
Puget Pascal IR (1) NAOS, AMBER, WIRCAM, VLTPF<br />
Rabou Patrick IR NAOS, VLTPF<br />
Stadler Eric IR MDM, NAOS, WIRCAM, VLTPF<br />
Zins Gérard IR AMBER, JMMC, EII<br />
Arezki Brahim IE AMBER, IONIC, MAII, IODA<br />
Delboulbé Alain AI AMBER, IONIC, MAII, IODA, VITRUV, WIRCAM<br />
Delfosse Xavier AA FOST JMMC<br />
Fraix-Burnet Didier CR SHERPAS AMBER<br />
Glück Laurence IE AMBER, JMMC<br />
Lagrange Anne-Marie DR FOST NACO, VLTPF<br />
Monin Jean-Louis PR FOST AMBER<br />
Petrucci Pierre-Olivier CR SHERPAS VITRUV<br />
Preis Olivier IE IONIC, VITRUV<br />
Note: 1 on leave from LAOG mid-2002<br />
Table 14.1: GRIL permanent staff. Those mostly involved in prospective and/or publishing in instrumental<br />
research are in the upper part of the list. Other are contributors at various levels in the GRIL activities. Note<br />
that 2 engineers are qualified to supervised PhDs (french ’HDR’).<br />
• MOEMS pour la correction <strong>de</strong> surface d’on<strong>de</strong> en optique adaptative, by Schwartz W., Beuzit J.-L., Kern<br />
P.; 2003 in Microsystèmes opto-électromécaniques, pp. 141-180<br />
• See section on valorisation for results on MMD <strong>de</strong>velopment (patents submission prevent publication)<br />
• Series ”Integrated optics for astronomical interferometry” in A&A<br />
• Planar integrated optics and astronomical interferometry, Kern, P.; Berger, J.-P.; Haguenauer, P.; Malbet,<br />
F.; Perraut, K.; 2001 ; C. R. Acad. Sci. Paris ; 2 ; 111-124<br />
• First Results with the IOTA3 Imaging Interferometer: The Spectroscopic Binaries lambda Virginis and WR<br />
140, Monnier, J. D.; Traub, W. A.; Schloerb, F. P.; Millan-Gabet, R.; Berger, J.-P.; Pedretti, E.; Carleton,<br />
N. P.; Kraus, S.; Lacasse, M. G.; Brewer, M.; Ragland, S.; Ahearn, A.; Coldwell, C.; Haguenauer, P.; Kern,<br />
P.; Labeye, P.; Lagny, L.; Malbet, F.; Malin, D.; Maymounkov, P.; Morel, S.; Papaliolios, C.; Perraut, K.;<br />
Pearlman, M.; Porro, I. L.; Schanen, I.; Souccar, K.; Torres, G.; Wallace, G.; 2004 ; Astrophysical Journal<br />
Letters ; 602 ; L57-L60<br />
• First observations with an H-band integrated optics beam combiner at the VLTI, Le Bouquin, J. B.;<br />
Rousselet-Perraut, K.; Kern, P.; Malbet, F.; Haguenauer, P.; Kervella, P.; Schanen, I.; Berger, J. P.;<br />
Delboulbe, A.; Arezki, B.; Schöller, M.; 2004 ; Astronomy and Astrophysics ; 424 ; 719-726<br />
• Infrared Imaging of Capella with the IOTA Closure Phase Interferometer, Kraus, S.; Schloerb, F. P.;<br />
Traub, W. A.; Carleton, N. P.; Lacasse, M.; Pearlman, M.; Monnier, J. D.; Millan-Gabet, R.; Berger,<br />
J.-P.; Haguenauer, P.; Perraut, K.; Kern, P.; Malbet, F.; Labeye, P.; 2005 ; The Astronomical Journal,<br />
Volume 130, Issue 1, 246-255<br />
140
• Tantalum superconducting tunnel junctions for infrared photon counting, Jorel, C.; Villégier, J.-C.; Feautrier,<br />
P.; Benoit, A.; 2004 ; Nuclear Instruments and Methods in Physics Research A ; 520 ; 516-518<br />
14.3 Industrial <strong>de</strong>velopment<br />
14.3.1 Patents<br />
Three applications have been filled regarding possible patents in the frame of our R&D activities on new<br />
<strong>de</strong>formable micro-mirrors. All three patents have now been issued. Details are given below:<br />
• ”Dispositif d’actionnement électrostatique miniature et installation comprenant <strong>de</strong> tels dispositifs”, European<br />
Patent, CNRS/CEA, FR0206293 from 23/05/2002. Patent hol<strong>de</strong>rs: J. Charton and E. Stadler.<br />
• ”Composant MEMS électrostatique permettant un déplacement vertical important”, French patent, CNRS/CEA,<br />
FR0351211 from 26/12/2003. Patent hol<strong>de</strong>rs: J. Charton and C. Divoux (CEA/LETI).<br />
• ”Miroir déformable magnétique”, French Patent, CNRS, FR0452342 from 12/10/2004. Patent Hol<strong>de</strong>rs:<br />
J. Charton, Z. Hubert, L. Jocou, E. Stadler, P. Kern and J.-L. Beuzit.<br />
Two applications are currently processed in the frame of our activities on future <strong>de</strong>tectors:<br />
• ”Détecteur et caméra spectroscopique interférentiels”, French Patent, UJF INPI 04/52992, applied December<br />
15th 2004. Patent Hol<strong>de</strong>rs: le Coarer, E., Benech, P.<br />
• ”Spectrographes à on<strong>de</strong> contra-propagative”, French Patent, UJF INPI 05/08429, applied August 8th<br />
2005. Patent Hol<strong>de</strong>rs: le Coarer, E., Benech, P., Blaize, S., Kern, P., Léron<strong>de</strong>l, G., Morand, A.<br />
14.3.2 Technological transfer<br />
After the commercial license agreements signed for the distribution of our magnetic <strong>de</strong>formable mirrors, it is<br />
inten<strong>de</strong>d to extend this industrial <strong>de</strong>velopment to other instrumental research results.<br />
14.4 Highlights<br />
The main facts related to our activities since 2001 are summarized below:<br />
• The NAOS (Nasmyth Adaptive Optics System) instrument for the VLT is now offered to the ESO astronomical<br />
community after a successful commissioning and science verification between November 2001 and<br />
August 2002.<br />
• Magnetic Deformable Mirrors are now fully functional and available to all interested parties through our<br />
industrial partners.<br />
• The <strong>de</strong>velopments of electrostatic <strong>de</strong>formable mirrors between LAOG and CEA/LETI is un<strong>de</strong>rway with<br />
a first fully functional 19-actuators laboratory prototype being characterized.<br />
• The “Planet Fin<strong>de</strong>r” proposal for a second generation instrument for the VLT led by LAOG was selected<br />
by the ESO STC in April 2005 after a successfull 2-year phase A study, awaiting formal <strong>de</strong>cision by the<br />
next ESO Council.<br />
• Development, Integration, Installation of the AMBER instrument to ESO. It is now offered to the ESO<br />
astronomical community for part of its mo<strong>de</strong>s and will be fully offered when the VLTI improvement plan<br />
is completed.<br />
141
• First fringes in the H band with 3 telescopes of IOTA by means of an integrated optics beam combiner<br />
(Monnier et al. 2004, Kraus et al. 2005)<br />
• Nulling of 10 −4 achieved on the ALCATEL Space MAII bench by using an integrated optics beam combiner<br />
<strong>de</strong>veloped un<strong>de</strong>r ESA contract.<br />
• First formal <strong>de</strong>monstration of single mo<strong>de</strong> guiding at 10 µm in the IODA project (Labadie et al. 2005)<br />
• Creation and <strong>de</strong>velopment of the Centre Jean-Marie Mariotti (JMMC) with partners. Consecutive creation<br />
of the European interferometry Initiative (EII) coupling interferometry networks of the OPTICON EC I3.<br />
• Development, Integration, Installation of the WIRCAM instrument to CFHT. It is now offered to the<br />
CFH community.<br />
14.5 Awards<br />
• The 52-actuator magnetic mirror has won the Photon d’Argent award of the Vitrine <strong>de</strong> l’innovation (second<br />
most innovative project) during the OPTO 2005 exhibition in September 2005<br />
• Pierre Kern received the Cristal du CNRS in 2005 for the quality and scope of his personal contribution<br />
to a number of R&D as well as large projects<br />
• Fabien Malbet received the COMPAQ/SF2A price in 2004 for his pioneering contribution in long-baseline<br />
near-infrared interferometry and its application to the study of young stars<br />
14.6 Acronyms<br />
• AMBER: near-infrared spectrograph for the VLTI<br />
• ANR Agence nationale <strong>de</strong> la recherche<br />
• ADONIS AO system installed on the ESO 3.6m telescope<br />
• API Antarctic Planet Interferometer<br />
• ARENA Antarctic Research, a European Network for Astronomy<br />
• AT VLTI auxiliary telescopes<br />
• CEA Atomic studies agency<br />
• CHARA Center for High Angular Resolution Astronomy Array<br />
• CNAP Conseil National <strong>de</strong>s Astronomes et Physiciens<br />
• CNES Centre National d’Etu<strong>de</strong>s Spatiales<br />
• CRTBT Centre <strong>de</strong> recherche <strong>de</strong>s très basses températures (CNRS)<br />
• MDM: Micro Deformable Mirrors<br />
• DRFMC (CEA) Département <strong>de</strong> Recherche Fondamentale <strong>de</strong> la Matière Con<strong>de</strong>nsée<br />
• EC European Community<br />
• EII European Interferometry Initiative<br />
• FALCON Fiber-spectrograph with Adaptive optics on Large fields to Correct at Optical and Near-infrared wavelengths<br />
• FLUOR Fiber-Linked Unit for Optical Recombination<br />
• FP Framework Programme (of EC)<br />
• GdR Groupement <strong>de</strong> recherche (CNRS)<br />
• GeeO : Groupement d’Electromagnétisme Expérimental et d’Optoélectronique - <strong>Grenoble</strong><br />
• GENIE Ground-based European Nulling Interferometer Experiment<br />
• GLAO Ground Layer Adaptive Optics<br />
• GTO Guarantee time observing<br />
• HRA High angular resolution<br />
• HARPS High Accuracy Radial velocity Planetary Search<br />
142
• I3 IInternational Integrating Infrastructure (of EC FP)<br />
• IMEP Institut <strong>de</strong> Microélectronique, Electromagnétisme et Photonique (INPG)<br />
• INPG Institut National Polytechnique <strong>de</strong> <strong>Grenoble</strong><br />
• IODA Integrated Optics for DArwin<br />
• IONIC Integrated Optics Near-Infrared Camera<br />
• IOTA Infrared Optical Telescope Array<br />
• JMMC: Jean-Marie Mariotti Center<br />
• JRA Joint research activity<br />
• KEOPS Kiloparsec Explorer for Optical Planet Search<br />
• LETI : <strong>Laboratoire</strong> d’Electronique <strong>de</strong> Technologie <strong>de</strong> l’Information (CEA)<br />
• LGGE <strong>Laboratoire</strong> <strong>de</strong> géologie et glaciologie (OSUG)<br />
• LPMC <strong>Laboratoire</strong> <strong>de</strong> Physicochimie <strong>de</strong> la Matière Con<strong>de</strong>nsée<br />
• MAII Multi-aperture Imaging Interferometer<br />
• MCAO Multi-Conjugate Adaptive Optics<br />
• NAOS: Nasmyth Adaptive Optics System<br />
• OCA Observatoire <strong>de</strong> la Côte d’Azur<br />
• ONERA Office national d’étu<strong>de</strong> et recherches aérospatiales<br />
• OSUG Observatoire <strong>de</strong>s sciences <strong>de</strong> l’Univers <strong>de</strong> <strong>Grenoble</strong><br />
• PdB Plateau <strong>de</strong> Bure (IRAM interferometer site)<br />
• PNPS Programme National <strong>de</strong> Physique Stellaire (CNRS)<br />
• STC Scientific and Technical Committee (of ESO)<br />
• STJ Super conducting jonctions<br />
• TGE Very large equipments<br />
• VITRUV: near-infrared imager for the VLTI<br />
• WIRCAM: Wi<strong>de</strong>-field InfraRed CAMera<br />
• XAO EXtreme AO<br />
143
144
Part VI<br />
TEAM SHERPA<br />
The two-flow paradigm for compact objets: accretion-ejection solution computed around<br />
a microquasar of M = 10M⊙ and fed with ˙ Macc = 0.01 ˙ MEdd. The color background is the<br />
logarithm of the <strong>de</strong>nsity (in cm − 3), black solid lines are the field lines and white solid lines<br />
are streamlines. The MHD jet launched from the accretion disc remains mildly relativistic.<br />
Above the black hole, time-<strong>de</strong>pen<strong>de</strong>nt pair creation leads to the formation of a ultrarelativistic<br />
beam, maintained warmed and confined by the outer MHD jet. This pair beam<br />
is responsible for both superluminal motions and very high energy emission of compact<br />
objects.<br />
145
146
Chapter 15<br />
Results<br />
15.1 History and group composition<br />
In the eigthies, the study of non-thermal phenomena in AGNs was the main research activity of Guy Pelletier,<br />
who came from the plasma physics community. This was essentially the only theoretical work in the laboratory<br />
(Dir. Alain Omont) which, at that time, was originally oriented towards Radio-Astronomy with a focus on the<br />
interstellar medium. This AGN activity then gave birth to a group in the early nineties when Gilles Henri,<br />
coming from the University of Paris XI got a permanent position at the University of <strong>Grenoble</strong> and when<br />
two brilliant stu<strong>de</strong>nts, Françoise Rosso and Jonathan Ferreira, were hired for a thesis program on Astrophysical<br />
Magnetohydrodynamics (MHD) with G. Pelletier. We thus started a larger activity <strong>de</strong>voted to accretion-ejection<br />
for both AGNs and Young Stellar Objects (hereafter YSOs) with the stu<strong>de</strong>nts and a new activity <strong>de</strong>voted to<br />
the High Energy aspect of AGNs with Gilles Henri (the first gamma spectra of some AGNs were about to be<br />
produced by EGRET).<br />
The laboratory was about to increase dramatically with the opening of Infra Red activity and the coming of<br />
a group involved on Young Stellar Objects was un<strong>de</strong>r discussion. We were particularly in favor of welcoming this<br />
new component because this was about to open a new field of collaboration in the laboratory and we warmly<br />
supported the arrival of Clau<strong>de</strong> Bertout and his team. Then the laboratory was metamorphosed and our group,<br />
which hired new permanent researchers from Toulouse (Pierre-Yves Longaretti and Didier Fraix-Burnet), took<br />
the name SHERPA (Sources of High Energy Relativistic Plasmas Accretion-ejection). It emphasizes both the<br />
type of objects we <strong>de</strong>al with, namely sources of high energy powered by accretion-ejection, and the type of<br />
physics we <strong>de</strong>velop, namely, MHD, relativistic plasma physics and transfer of high energy radiation.<br />
Table 1 lists the current permanent staff with their main activity. In 2005, the group hosts Yaël Fuchs<br />
with an ATER position (one year) and three graduate stu<strong>de</strong>nts: Clément Cabanac (started in 2003), Geoffroy<br />
Lesur (started in 2004) and Nicolas Bessolaz (started in 2004, in co-direction with the FOST team). In Fall<br />
2005 a post-doc, Claudio Zanni, will join the group for 2 or 3 years, as well as another PhD stu<strong>de</strong>nt Timothée<br />
Boutelier.<br />
15.2 Specific approach<br />
Among the teams working on MHD astrophysics, high energy cosmic phenomena and the environment of compact<br />
objects, we adopted the following attitu<strong>de</strong>. Instead of running after scoops, we firmly <strong>de</strong>ci<strong>de</strong>d to <strong>de</strong>velop<br />
ground researches about the physical issues and the interrelations between the gross phenomena governed by<br />
gravitation and MHD, the kinetic level of relativistic plasmas, including the physics of particle acceleration, and<br />
the physics of the high energy photon emission. Therefore, we are mostly involved in theoretical <strong>de</strong>velopments<br />
together with numerical simulations. However, we also provi<strong>de</strong> our expertise by participating in large collaborations<br />
organized for the ”exploitation” of facilities in the whole energy range from millimeter to TeV gamma<br />
range.<br />
147
Table 15.1: List of the permanent SHERPA group members in 2005.<br />
Name Gra<strong>de</strong> Specialty<br />
Jonathan Ferreira MdC accretion-ejection, MHD<br />
Didier Fraix-Burnet CR1 astrocladistics<br />
Gilles Henri Prof high energy phenomena<br />
Pierre-Yves Longaretti CR1 MHD instabilities and transport<br />
Guy Pelletier Prof (group lea<strong>de</strong>r) relativistic plasma physics, MHD<br />
Pierre-Olivier Petrucci CR2 high energy phenomena<br />
Peggy Varnière CR2 (starting Fall of 2005) MHD simulations<br />
15.3 Accretion-Ejection<br />
15.3.1 The self-similar mo<strong>de</strong>l<br />
Accretion-ejection phenomena are common-place in astrophysics. They are present in the cores of active galaxies<br />
(AGNs) and quasars but also around compact objects such as X-ray binaries or even some cataclysmic variables<br />
within our galaxy. It is the major physical process governing the growth rate of young stellar objects (YSOs).<br />
Accretion-ejection is therefore a process of major importance. It has long been recognized that the high <strong>de</strong>gree<br />
of collimation exhibited by jets from AGNs or YSOs requires a self-confinement process which can only be<br />
provi<strong>de</strong>d by large scale magnetic fields carried in along the jet. This gave rise to MHD mo<strong>de</strong>ls of jet formation<br />
and collimation. On the other hand, all these objects display a correlation between accretion and ejection<br />
observational signatures (Hartigan, Edwards & Ghandour 1995, ApJ, 452, 736). These correlations gave birth<br />
to the i<strong>de</strong>a that accretion and ejection were actually inter<strong>de</strong>pen<strong>de</strong>nt processes.<br />
Our team was the first to i<strong>de</strong>ntify the concept of a Magnetized Accretion-Ejection Structure (MAES, Ferreira<br />
& Pelletier 1993, A&A, 276, 625). In such a structure a large scale magnetic field of bipolar topology is<br />
threading the disk. The field exerts a torque which takes away the disk angular momentum thereby allowing it<br />
to accrete towards the central object. A turbulence is nee<strong>de</strong>d in or<strong>de</strong>r to allow mass to steadily diffuse through<br />
the magnetic field. This angular momentum and energy is then transferred back to a small fraction of the<br />
disk material which gives rise to a self-confined MHD jet. In contrast with other teams, the MAES has been<br />
computed by solving the exact equations of both the disk and the jets: usually, the disk is either ignored (taken<br />
as a mere boundary condition, e.g. Blandford & Payne 1982, MNRAS, 199, 883, Shu et al. 1994, ApJ, 429, 781)<br />
or its vertical structure is cru<strong>de</strong>ly approximated (e.g. Wardle & Königl 1993, 410, 218, Li 1995, ApJ, 444, 848).<br />
By taking into account all terms (which was possible thanks to a self-similar ansatz), we were able to provi<strong>de</strong><br />
the full parameter space of MAES with strong consequences on the level of the required MHD turbulence (Casse<br />
& Ferreira 2000a, A&A, 353, 1115, Casse & Ferreira 2000b, A&A, 361, 1178). This work has been recently<br />
exten<strong>de</strong>d by producing the only solutions of jets from accretion disks that cross the three MHD critical points<br />
(Ferreira & Casse 2004).<br />
We are now endowed with the only available mo<strong>de</strong>l in the literature of disk-driven jets which provi<strong>de</strong>s all<br />
fields (<strong>de</strong>nsity, velocity and magnetic fields) as functions of the disk physical conditions in a consistent way.<br />
15.3.2 Application to different astrophysical contexts<br />
Since jets from YSOs are cooling by optically thin emission lines it is possible to <strong>de</strong>rive strong constraints on<br />
their dynamics and discriminate mo<strong>de</strong>ls. Thus, most past work has been <strong>de</strong>voted to YSOs. The application of<br />
the MAES mo<strong>de</strong>l to compact objects is only beginning, with a focus on ”microquasars”.<br />
Young Stellar Objects.<br />
Using the self-similar MAES mo<strong>de</strong>l, we were able to compute synthetic observations and compare them<br />
to real observations. A previous work done in collaboration with observers (Garcia et al. 2001a, A&A, 377,<br />
589, Garcia et al. 2001b, 377, 609) showed that most of the T-Tauri optical jet properties (line profiles, flux,<br />
jet velocities, evolution of the jet diameter along the distance) could be easily explained by disk-driven jets.<br />
148
Figure 15.1: A standard accretion disk (SAD) fed with ˙ Ma = 0.01LEdd/c 2 is established down to a radius rJ<br />
which marks the transition towards a jet emitting disk (JED), settled down to the last stable orbit. The JED<br />
is driving a mildly relativistic self-collimated electron-proton jet (MAES) which, when suitable conditions are<br />
met, is confining and inner ultra-relativistic electron-positron beam. Field lines are drawn in red solid lines and<br />
the number <strong>de</strong>nsity is shown in greyscale (log 10 n/m −3 ).<br />
However, observations require a rather large ejection to accretion ratio which can only be attained when there<br />
is some heat <strong>de</strong>position at the disk surface layers. This was again confirmed by near-IR mo<strong>de</strong>ling of the jet<br />
emission (Pesenti et al. 2003). Finally, when taking into account observational biases in the <strong>de</strong>tection of jet<br />
rotation, disk-driven mo<strong>de</strong>ls with heat <strong>de</strong>position are the best candidates (Pesenti et al. 2004, Ferreira et al.<br />
2005, submitted). This work has been done in collaboration with members of the FOST team. Such heat<br />
<strong>de</strong>position has to come from local dissipation of the accretion energy, even in the presence of illumination by<br />
stellar UV and X-ray fluxes (Garcia et al. 2005, submitted).<br />
X-ray Binaries.<br />
Microquasars are X-ray binaries where the primary is a black hole, displaying jets with an intriguing time<br />
variability. In<strong>de</strong>ed, they change their spectral state from a ”High/Soft” (dominated by a soft disk component)<br />
to a ”Low/Hard” (dominated by a hard power-law emission) state on time scales of hours. Jets are only seen<br />
during the Low/Hard state. Moreover, it has been recently shown that this evolution is following an hysteresis<br />
cycle. Therefore, these objects provi<strong>de</strong> valuable clues on the secular evolution of the accretion-ejection process<br />
(their dynamical time scale is the millisecond). Such transitions between spectral states would be unobservable<br />
for AGNs.<br />
Within our framework, a MAES is settled in the innermost disk regions surroun<strong>de</strong>d by a standard accretion<br />
disk as illustrated in Fig. 15.1 (Ferreira et al. 2005). This picture allows to explain several aspects of the<br />
microquasar phenomenology: jet production in the Low/Hard state, jet quenching in the High/Soft state,<br />
superluminal flares (pair plasma) un<strong>de</strong>r certain circumstances. Although each spectral state can be explained<br />
by varying the relative importance of each component, several crucial questions remain to be investigated. This<br />
requires a coupling between MHD and high energy physics and is therefore a central theme of our group.<br />
149
15.4 Transport phenomena in accretion-ejection flows<br />
The existence of accretion-ejection structures raises a number of prominent issues, which, for most of them,<br />
have been around from the very beginning of this field of research.<br />
15.4.1 Jet stability<br />
The exceptional propagation length of jets, as compared to their radii, raises the question of the physical<br />
mechanisms responsible for their stability. This question has at least two different aspects:<br />
(1) Jet global stability properties. Purely hydrodynamical jets are quickly <strong>de</strong>stroyed due to the <strong>de</strong>velopment<br />
of the Kelvin-Helmholtz instability. MHD jets seem to be more stable with respect to Kelvin-Helmholtz mo<strong>de</strong>s.<br />
However, such MHD jet are prone to be unstable with respect to purely MHD (current- and pressure-driven)<br />
instabilities, the outcome of which is still unknown on theoretical grounds. These instabilities are well-known<br />
to be quite disruptive in the fusion context, so that the very small level of research activity in the astrophysics<br />
community on these issues is all the more surprising.<br />
(2) Particle acceleration. However, one certainly does not want to quench every possible mo<strong>de</strong> of instability<br />
in MHD jets as some turbulence is required to accelerate the non-thermal particle populations which are<br />
responsible for the high energy emission of these objects. In particular, in the framework of the two-flow mo<strong>de</strong>l<br />
<strong>de</strong>veloped by the SHERPA team, it is essential to un<strong>de</strong>rstand and characterize the processes responsible for the<br />
turbulent stirring of the pair plasma, which tap the energy reservoir of the large scale MHD jet.<br />
In or<strong>de</strong>r to make progress on these issues, the effect of pressure- and current-driven instabilities in jets are<br />
examined ab initio. Pressure-driven instabilities are expected to be most disruptive in jets confined by the<br />
hoop-stress, and a linear analysis of the problem has been un<strong>de</strong>rtaken (Kersale, Longaretti & Pelletier, 2000,<br />
A&A, 363,1166; Longaretti 2003; Longaretti & Baty in preparation). A complete review of the question of jet<br />
structure and stability, based on both the astrophysical and fusion literature, has also been written (Longaretti<br />
2005).<br />
15.4.2 Transport in accretion disks<br />
The question of mass and angular momentum transport in accretion disks is one of the ol<strong>de</strong>st issues in this branch<br />
of astrophysics, and has not yet been resolved in a satisfying way. In spite of the remarkable progress un<strong>de</strong>rgone<br />
in the last fifteen years, with the (re)discovery of the “Magneto-Rotational Instability” (MRI, Balbus & Hawley<br />
1991, ApJ, 376, 214), and the (essentially numerical) characterization of the induced turbulent transport in the<br />
nonlinear regime (e.g. Stone et al. 1996, ApJ, 463, 656), many issues are still acutely open:<br />
(1) Not all disks, or disk regions, are ionized enough to sustain MHD activity (e.g. Gammie 1996, ApJ, 457,<br />
355, Matsumura & Pudritz 2003, ApJ, 598, 645). The transport in these regions must therefore be sustained<br />
through non-MHD mechanisms.<br />
(2) The accretion-ejection structures most actively studied in our group do require a fairly high level of turbulent<br />
resistivity to be self-consistently maintained (Ferreira & Pelletier 1995, A&A, 295, 807). It is unclear<br />
whether the MRI can provi<strong>de</strong> it.<br />
To settle these questions, we have first addressed and completely reinvestigated the old issue of the existence<br />
of subcritical turbulence in keplerian flows. The un<strong>de</strong>rlying i<strong>de</strong>a is that all linearly stable flows accessible to<br />
laboratory experiments are observed to un<strong>de</strong>rgo a transition to turbulence (called subcritical). The initial<br />
proposal by Shakura & Sunyaev (1973, A&A, 24, 337) was that such a mechanism was at work in keplerian<br />
disks (which are hydrodynamically stable). This picture has given rise to controversial points of view in the<br />
astrophysics literature (Balbus, Hawley & Stone 1996, ApJ, 467, 76; Richard & Zahn 1999, A&A, 347, 734).<br />
Due to the formidable complexity of the problem, little progress had been accomplished on this issue at a<br />
fundamental level, until the last <strong>de</strong>ca<strong>de</strong>, where an interesting breakthrough has been operated in the fluid<br />
150
mechanics community, for non-rotating shear flows. Based on this new un<strong>de</strong>rstanding, the question has been<br />
reinvestigated in rotating flows (such as the keplerian flows), through i/ a phenomenological analysis (Longaretti<br />
2002); ii/ a reinvestigation of all the relevant laboratory experimental data (Longaretti and Dauchot 2005;<br />
Longaretti and Dauchot, in preparation; Dubrulle et al. 2005); and iii/ numerical simulations (Lesur and<br />
Longaretti 2005). This work has lead to the conclusion that a stabilizing rotation does not quench the transition<br />
to turbulence, but nevertheless consi<strong>de</strong>rably reduces the efficiency of the subcritical turbulent transport, thereby<br />
settling this old dispute.<br />
Geoffroy Lesur has started a PhD in September 2004, un<strong>de</strong>r the supervision of Pierre-Yves Longaretti, with<br />
the aim to investigate in a more systematic way the question of turbulent transport in disks and jets, both from<br />
analytic and numerical points of view.<br />
15.5 Physics of high energy sources<br />
15.5.1 Seyfert galaxies<br />
Seyfert galaxies are strong X-ray emitters with a characteristic X-ray spectra. It is roughly power-law like<br />
above 2 keV, with the presence of a high energy cut-off near 100 keV (e.g. Petrucci et al. 2001, ApJ, 556,<br />
716; Zdziarski et al. 2000, ApJ, 542, 703). Secondary components, like a fluorescent iron line near 6.4 keV<br />
and a bump in the 10-50 keV range are also generally present. The X-ray emission is generally supposed to<br />
be produced by a hot and optically thin thermal plasma (a corona) localized above the accretion disk and<br />
comptonizing the disk photons. The secondary components are thought to result from the Compton reflection<br />
of the X-rays on the disk surface. Due to the lack of sensitivity in the hard X-ray/soft gamma ray energy range<br />
(0.1-1 MeV) of the <strong>de</strong>tectors, the real nature of the high energy continuum of Seyfert galaxies remains unclear.<br />
We have recently tested two different geometries of the disk-corona configuration using the most well adapted<br />
data for the study of the Seyfert high energy continuum i.e. the BeppoSAX 1 brightest Seyfert sample (Petrucci<br />
& Dadina 2005 in preparation). This subsample contains 28 objects. It appears that both geometries agree<br />
with the data but more importantly, we show that the behaviors of the physical parameters of the mo<strong>de</strong>ls<br />
(mainly the temperature and optical <strong>de</strong>pth of the X-ray corona) are strongly geometry <strong>de</strong>pen<strong>de</strong>nt, resulting in<br />
completely different physical interpretations. This work is an extension of previous works done on a smaller<br />
sample (Petrucci et al, 2000, ApJ, 540, 131; Petrucci et al. 2001, ApJ, 556, 716) and un<strong>de</strong>rlines the weakness<br />
of the actual constraints.<br />
Stronger and less ambiguous constraints on the nature of the coronal plasma can be obtained from variability<br />
studies. For example, thermal mo<strong>de</strong>ls, where hot and cold phases are in radiative equilibrium, predict that the<br />
X-ray spectrum of the sources should har<strong>de</strong>n when the corona temperature increases (Haardt et al. 1997, ApJ,<br />
476, 620) while non-thermal mo<strong>de</strong>ls predict the reverse (Petrucci et al. 2001, A&A, 374, 719). The analysis of<br />
the ∼1 month simultaneous IUE/RXTE monitoring campaign on NGC 7469, performed in 1996, appears to be<br />
in agreement with thermal comptonization emission (Nandra et al. 2000, ApJ, 544, 734). We have performed<br />
a more recent reanalysis of these data with realistic comptonization co<strong>de</strong>s that gives another support to this<br />
interpretation (Petrucci et al. 2004). Missions with X-ray/γ-ray broad band capabilities and higher sensitivity,<br />
like the future ASTROE-2 mission, are required to progress in this field.<br />
On the other hand, the highly sensitive instruments of the XMM-Newton satellite enable very new and<br />
exciting results concerning the fluorescent iron line. Broad iron lines are clearly present in some Seyferts and in<br />
objects like MCG-6-30-15, their broad profiles suggest the presence of spinning black hole, close to the extreme<br />
Kerr value (Fabian et al., 2000, PASP, 112, 1145) and require very steep disk emissivity laws (Wilms et al. 2001,<br />
MNRAS, 328, L27; Fabian et al. 2002, MNRAS, 335, L1), steeper than standard accretion disk one. This is<br />
in agreement with the mo<strong>de</strong>l we proposed some years ago where the irradiating X-ray source was concentrated<br />
on the disk axis, above the black hole (Henri & Petrucci 1997, A&A, 326, 87; Petrucci & Henri 1997, 326, 99<br />
but see also Martocchia & Matt 1996, A&A, 282, L53; Martocchia et al. 2002, A&A, 383, L23). More recently,<br />
redshifted narrow iron lines have been also observed in an increase number of objects (e.g. Yaqoob et al. 2003,<br />
ApJ, 596, 85; Longinotti et al. 2004; Porquet et al. 2004, A&A, 427, 101; Turner et al. 2004, ApJ, 603, 62;<br />
Iwasawa et al. 2004, MNRAS, 335, 1073). These lines can be interpreted as signatures of small magnetic flares<br />
illuminating small part of the accretion disk. We are investigating the presence of such a line in the Seyfert 1<br />
1 BeppoSAX was an Italian-Dutch satellite covering the 0.1-200 keV energy range. It stopped observing in 2003.<br />
151
Figure 15.2: Spectral energy distribution of Markarian 501 during the flaring states of April 7 and 16, 1997,<br />
fitted by a simple time averaged mo<strong>de</strong>l (Saugé & Henri 2004). Dashed line : simulated spectrum before intrinsic<br />
absorption ; solid line : spectrum after correcting form intrinsic absorption. The grey points are the raw data<br />
from CAT observations, and open squares are the data corrected from extragalactic absorption.<br />
galaxy Mkn 841. In a first XMM observation, we observed a rapidly variable narrow iron line in this source<br />
(Petrucci et al. 2002). Due to the short exposure (2×15 ks), the statistic was not high enough to contrain<br />
the origin of the variability. A new XMM observation, longer (45 ks+25 ks) than the previous one, has been<br />
performed recently (January 2005). Work is in progress to carefully analyse these data and to better <strong>de</strong>termine<br />
the origin of the line variability.<br />
15.5.2 Blazars and the “two-flow” mo<strong>de</strong>l<br />
A subclass of AGNs is formed by the radio-louds objects, characterized by an intense radio luminosity : they<br />
comprise radio-galaxies and quasars. When imaged through interferometric techniques, the radio emission is<br />
found to arise from powerful jets emitted from the central engine in the galaxy core. The radio emission is highly<br />
polarized and rapidly variable, and is thought to be the result of incoherent synchrotron emission, produced by<br />
non thermal, highly relativistic particles in the presence of magnetic field, emitted in relativistic jets with high<br />
Lorentz factors. The most powerful and variable objects are called blazars. This property is also responsible<br />
for the appearance of superluminal motions at parcec scale, i.e. apparent velocity larger than the velocity of<br />
light, which imply a lower limit on the value of the Lorentz factor, which is usually about 10.<br />
In the early 90s, the <strong>de</strong>velopment of space gamma-ray astronomy (particularly the CGRO observatory) and<br />
ground based Atmospheric Cerenkov Telescopes (ACT), has revealed that many blazars are also strong gammaray<br />
emitters, the highest energy photons being <strong>de</strong>tected above the TeV energy through ACT like Whipple. A<br />
new generation of ACT is currently growing, the most remarkable and probably best instrument being the HESS<br />
telescopes in Namibia (see international collaborations). Gamma-ray photons, like radio emission, are thought<br />
152
to be produced in the relativistic jets, explaining the high luminosity without gamma-gamma absorption.<br />
There are three processes, still discussed, to explain the generation of extragalactic jets : i) the jet launching<br />
by a magnetized accretion disk, ii) the Poynting flux generation by a magnetized spinning Black Hole, iii)<br />
the Compton rocket propulsion in the anisotropic radiation field of an accretion disk (purely hydrodynamical<br />
processes have been discar<strong>de</strong>d). All the three scenarii have problems to account for observations. The first one<br />
turns out to be the most powerful, the most collimating, and able to explain the power input in the FR2 hot<br />
spots, which is a sizable fraction of the accretion power. To be powerful, it requires that the jet extracts most<br />
of the angular momentum of the disk, which, in turn, <strong>de</strong>eply modifies the accretion regime (uaccr ∼ h/rVkep<br />
instead of h 2 /r 2 VK like in standard accretion disk) and it can be shown that the accretion flow is neither a<br />
SAD nor an ADAF; we call it “JED” for Jet Emitting Disk. But it turns out that this process cannot generate<br />
highly relativistic flow because of its baryon load. The second one is less powerful, has a much less collimating<br />
property and particularly suffers of the efficient Compton drag exerted by the accretion disk radiation field.<br />
The third one leads to a rapid <strong>de</strong>cay when the electron-positron plasma cools by Compton radiation.<br />
A priori there is no reason to assess that only one of these processes is at work. How to avoid the two others?<br />
The general solution is a combination of the three. In or<strong>de</strong>r to explain radio observations, Guy Pelletier (1985,<br />
Congr?s <strong>de</strong> la Soci?t? Fran?aise <strong>de</strong> Physique) proposed that the jets could harbour a double structure: a strong,<br />
only mildly relativistic jet (v ∼ 0.5c) emitted by the accretion disk, through the MHD mechanism <strong>de</strong>scribed<br />
Sect. 15.3, and a highly relativistic beam of electron-positron pairs, propagating insi<strong>de</strong> this jet whatever its<br />
production process (Pelletier et al. 1988, Phys Rev A, 38, 2552, Sol et al. 1989, A & A, Pelletier & Roland<br />
1989, A&A, 224, 24, etc.). In a second stage, the mo<strong>de</strong>l has been more elaborated in or<strong>de</strong>r to explain the<br />
discovery of the gamma emission of Blazars. The pair plasma of the relativistic beam is not only channeled<br />
by the MHD jet, but also heated by the MHD turbulence (Henri & Pelletier 1991, ApJ, 383, L7), which<br />
allows the Compton Rocket to work. Only this beam would be responsible for all relativistic phenomena,<br />
superluminal motions and non thermal radio-to-gamma-rays emission (e.g. Marcowith, Pelletier & Henri 1997,<br />
A&A, 323, 271). This ”two-flow” structure solves most theoretical problems associated to the generation of<br />
the jet, explaining for exemple the relativistic motion by an anisotropic Inverse Compton effect (Renaud &<br />
Henri 1998, MNRAS, 300, 1047). We have <strong>de</strong>veloped <strong>de</strong>tailed radiative calculations, showing that the non<br />
thermal emission could be very well explained by the mo<strong>de</strong>l. In the frame of Ludovic Saugé’s thesis, <strong>de</strong>fen<strong>de</strong>d<br />
in 2004, we have investigated the influence of the particle energy distribution function (EDF), exploring the<br />
consequences of using a quasi-monoenergetic EDF (more exactly a relativistic quasi-maxwellian, Saugé & Henri<br />
2004) instead of a multi power-law used by most authors. We have shown that such a distribution applies very<br />
well to TeV blazars (Fig. 15.2). We have also <strong>de</strong>veloped a full time-<strong>de</strong>pen<strong>de</strong>nt mo<strong>de</strong>l <strong>de</strong>scribing the evolution<br />
of the pair plasma coupled with the turbulence. This mo<strong>de</strong>l is un<strong>de</strong>rgoing improvements in or<strong>de</strong>r to allow<br />
<strong>de</strong>tailed comparisons with observations (particularly the recent multiwavelength campaigns led by the HESS<br />
collaboration).<br />
This double ejection mo<strong>de</strong>l has been mostly <strong>de</strong>veloped in the environment of Schwarzschild Black Holes.<br />
In the case of a Kerr Black Hole, we expect that the Poynting flux generated pair beam will <strong>de</strong>cay un<strong>de</strong>r<br />
usual conditions in AGNs and that only the Compton Rocket would work. However some situations where the<br />
opacity to pair creation would be lower would give more chance to the Blandford-Znajek to contribute. A three<br />
process ejection could even be at work when the opacity condition varies in the nucleus, with Blandford-Znajek<br />
process alternately at work when the opacity is low, the Compton rocket at work when the opacity is high (see<br />
explanations in ”Black Hole induced ejections” GP 2005).<br />
15.5.3 Microquasars<br />
Another class of compact objects is represented by the so-called X-ray binaries, in which a neutron star or a<br />
stellar mass black hole is associated with a normal star in close orbit, accreting matter from its companion. Some<br />
objects have shown phenomena very similar to quasars, exhibiting strong variable radio emission, superluminal<br />
motion, and possibly gamma-ray emission. As they can be consi<strong>de</strong>red as reduced version of quasars (the central<br />
object being 10 8 times as light as supermassive AGNs black holes), they are often called ”microquasars”. We<br />
have un<strong>de</strong>rtaken the application of our mo<strong>de</strong>l of relativistic jets to the ejection observed in microquasars, in<br />
connection with a more general scheme (Ferreira et al. 2005). We explain the various states of these objects by a<br />
transition between a standard accretion disk (SAD) and a jet emitting disk (JED). In this frame, the relativistic<br />
ejections could be associated with the explosive formation of <strong>de</strong>nse pair plasma during so-called ”intermediate”<br />
153
states, combining a still powerful jet and a luminous accretion disk. In these states, disk photons can be scattered<br />
up to very high energy by non thermal particles from the jet, which would produce enough gamma-ray photons<br />
to trigger pair production. Detailed quantitative calculations are un<strong>de</strong>r work.<br />
In another work, with the PhD stu<strong>de</strong>nt Cl?ment Cabanac, we are studying the time behavior of X-ray<br />
binaries observed with the hard X and γ-rays satellite INTEGRAL. We are currently <strong>de</strong>veloping numerical<br />
tools to extract the time information from the raw data, especially the presence of quasi-periodic oscillations<br />
(QPO) that have been commonly <strong>de</strong>tected by the RXTE satellite. The origin of these QPO is still disputed<br />
and an important question is their energy spectrum. We are <strong>de</strong>veloping in parallel a theoretical mo<strong>de</strong>l for these<br />
QPO based on an instability at the transition region between the SAD and the JED.<br />
15.6 Relativistic Plasmas and Cosmic Rays<br />
The non-thermal radiation from Black Hole environments is emitted by a relativistic plasma generated in the<br />
jets. Therefore high energy radiation (including TeV gamma rays, cosmic rays and possible neutrinos) is an<br />
important consequence of accretion-ejection flows around Black Holes. These relativistic plasmas are generated<br />
by specific dissipation mechanisms occurring at relativistic shocks and magnetic reconnections that require some<br />
theoretical <strong>de</strong>velopments. Moreover the dynamics of these accretion-ejection flows cannot be fully mastered<br />
without a significant un<strong>de</strong>rstanding of these microphysics processes. Some progress have been recently done in<br />
our team on these topics which are at the forefront of the physics of the so-called ”Astroparticle Science”.<br />
15.6.1 Relativistic plasmas<br />
Relativistic aspect of the accretion-ejection phenomenon.<br />
The issue of the formation of relativistic jets involves three important intricate problems, namely, the crossing<br />
of critical surfaces, collimation and conversion of the Poynting flux into matter-energy flux. These problems<br />
have been addressed in a synthesis that will appear in a collective book organized by R. Blandford and M.<br />
Lyutikov (Pelletier 2005).<br />
A major problem of the physics of accretion disks is the excitation of a turbulence state able to efficiently<br />
transfer the angular momentum of matter in or<strong>de</strong>r that it progressively falls on the central Black Hole. In the<br />
nineties, a successful solution has been proposed with the so-called ”Magneto-Rotational Instability”. We have<br />
exten<strong>de</strong>d the analysis of the instability to the case of a Kerr Black Hole and found an expected intensification<br />
and a wi<strong>de</strong>r window of the instability, that makes it compatible with the intense magnetic field required for<br />
launching jets, <strong>de</strong>spite the stabilizing ten<strong>de</strong>ncy of its tension effect. The analysis has been presented in the<br />
same chapter as before and will be <strong>de</strong>veloped in a forthcoming paper.<br />
Magnetic reconnection in relativistic regime.<br />
Nowadays the process of ”magnetic reconnection” is invoked in or<strong>de</strong>r to convert Poynting flux into matter<br />
energy flux and radiation in ultra-relativistic flows. Only very fast reconnection processes can be relevant in this<br />
context. Now standard reconnection processes based on the generalization of the Sweet-Parker scheme are too<br />
slow. New investigations in Tokamaks and space plasma physics revealed a new mechanism that turns out to be<br />
in<strong>de</strong>pen<strong>de</strong>nt on dissipation and fast. We are extending this approach to relativistic plasmas. A fair <strong>de</strong>scription<br />
of the phenomenon can be obtained in the frame of an appropriate modification of relativistic MHD for both<br />
baryon loa<strong>de</strong>d plasmas and e + − e − -plasmas. This has been presented in a first publication (Pelletier 2005) and<br />
a paper on relativistic reconnection is to be submitted (Pelletier & Longaretti 2005).<br />
15.6.2 Cosmic Rays<br />
Transport of Cosmic Rays in chaotic magnetic fields.<br />
The properties of the transport of Cosmic Rays in weak turbulence theory are known since the seventies.<br />
154
Figure 15.3: The spectrum of cosmic rays at a relativistic shock. This spectrum appears as the envelope of<br />
Fermi cycles (i.e. cosmic rays of large mean free path cross the shock front back and forth several times and gain<br />
energy at each crossing cycle downstream-upstream-downstream), the first corresponding to an amplification of<br />
the cosmic ray energy from its initial value ɛ0 by a factor Γ 2 , and the subsequent ones to an amplification by a<br />
factor 2.<br />
Because we crucially need to know them in the strong turbulence regime, especially in relation with the new<br />
investigations concerning the Ultra-High-Energy Cosmic Rays, we have un<strong>de</strong>rgone a systematical study of the<br />
transport, by combining theoretical and semi-analytical approaches with Monte-Carlo numerical simulations<br />
(Casse, Lemoine & Pelletier 2002). We have generalized the result of weak turbulence for the pitch angle diffusion<br />
and for the spatial diffusion along the magnetic field, as a function of the characteristics of the turbulence<br />
spectrum and the particle rigidity. But, as for the transverse diffusion with respect to the mean field, the<br />
behavior is <strong>de</strong>eply different and controlled by the chaotic aspect of the field lines. Furthermore, the diffusion<br />
at Larmor radii larger than the coherence length of the magnetic field does not stop sud<strong>de</strong>nly, the diffusion<br />
coefficient increases proportionally to the square of the particle energy.<br />
Fermi acceleration in relativistic regime with magnetic fronts and shocks.<br />
The enigma of the existence of Ultra High Energy Cosmic rays can be solved along two different but not<br />
exclusive ways : either by a ”bottom up” scenario where the UHECRs are generated by an acceleration process<br />
in the high energy astrophysical sources, or by a ”top down” scenario where some quantum objects, proposed by<br />
a new physics beyond the standard mo<strong>de</strong>l of particle physics, <strong>de</strong>cay and produce particles in this energy range.<br />
The Pierre Auger Observatory will soon provi<strong>de</strong> a crucial answer to this question. In<strong>de</strong>ed we will soon know<br />
whether there exists a particle spectrum beyond the ”GZK limit” (which is the energy threshold beyond which<br />
protons loose energy by producing mesons through collisions with the CMB-photons), revealing a generation of<br />
Cosmic Rays that would not come from extragalactic sources. We have contributed to the ”bottom up” scenario<br />
by studying the relativistic regime of Fermi acceleration, necessary for the Cosmic Rays to reach energies of<br />
or<strong>de</strong>r 10 20 eV in the consi<strong>de</strong>red sources (AGNs and Gamma-Ray Bursts or GRBs). We have <strong>de</strong>veloped the<br />
Fermi acceleration in relativistic regime along two different ways : with relativistic fronts and with relativistic<br />
shocks. When an ensemble of magnetic relativistic fronts propagate with relative speeds that are mildly relativistic,<br />
like in GRBs, the elastic scattering of magnetic fronts generates an efficient Fermi acceleration that<br />
we applied to GRBs (see next paragraph). As for the case of a relativistic shock, Martin Lemoine and G.P.<br />
have <strong>de</strong>veloped a combined theoretical and numerical study. The formation of the energy spectrum has been<br />
analyzed confirming a recent analysis proposed by Achterberg and Gallant (1999, MNRAS, 305, L6) and the<br />
time scales of the process have been <strong>de</strong>termined. Reliable laws for the generation of Cosmic Rays in relativistic<br />
flows have therefore been provi<strong>de</strong>d (Fig. 15.3).<br />
155
Excitation of turbulence by Cosmic Rays upstream a shock and consequences for the transport and the Fermi<br />
acceleration.<br />
The results we obtained on the transport of Cosmic Rays make its <strong>de</strong>pen<strong>de</strong>nce on the MHD turbulence<br />
spectrum precise. There exist semi-phenomenological theories of inertial turbulence spectra for common situations<br />
where the turbulence is excited at large scales and then casca<strong>de</strong>s over several <strong>de</strong>ca<strong>de</strong>s towards smaller<br />
scales where the dissipation takes place. Moreover the Reynolds numbers in astrophysical media are very large.<br />
However, the turbulence excited upstream astrophysical shocks is of a particular nature. In<strong>de</strong>ed it is excited<br />
by an instability resulting from the acceleration of Cosmic Rays at the shock and the instability amplifies the<br />
MHD mo<strong>de</strong>s over all scales through a resonnant regime (larger scales) and a non-resonnant regime (shorter<br />
scales). We have thus un<strong>de</strong>rgone the calculation of the turbulence spectra and the transport coefficients. Then<br />
we examined the consequences of the excitation of MHD turbulence on the energetic balance and the final<br />
spectrum of the Cosmic Rays that is steepened. This theoretical effort was ma<strong>de</strong> necessary by the indications<br />
<strong>de</strong>livered by the new observations of supernovae remnants by Chandra and XMM. Our theory incorporates not<br />
only the newest <strong>de</strong>velopments on anisotropic MHD turbulence but also an important effect: the backscattering<br />
of progressive Alfvén mo<strong>de</strong>s off sound waves (more precisely the slow magneto-sonic waves). These studies have<br />
been realized with Martin Lemoine, Alexandre Marcowith (CESR) and G.P. (in course of publication).<br />
High energy emission and Cosmic Rays from Gamma-Ray Bursts<br />
Gamma-Ray Bursts (GRBs) are phenomena radiating as much energy as supernovae but in a very short<br />
time, a few seconds or even less. The collimation of the ultra relativistic flows involved in GRBs strongly<br />
amplifies the energy flux. Un<strong>de</strong>r the less favorable hypothesis about the magnetic field and its irregularities, it<br />
has been shown that Cosmic Rays un<strong>de</strong>rgoing scattering off relativistic magnetized fronts (revealed by the light<br />
curves) could in<strong>de</strong>ed reach the UHE range (Gialis & Pelletier 2004). The performances of GRBs as sources of<br />
high energy radiation in the form of photons and neutrinos have been estimated (Gialis & Pelletier 2005). A<br />
gamma diagnosis of UHECR generation is proposed; the diagnosis in the range of a few tens of GeV appears<br />
to be non-ambiguous, because this signal of hadronic origin should not be contaminated by inverse Compton<br />
emission by electrons which is <strong>de</strong>eply in the Klein-Nishina regime. We are eagerly waiting for the observations<br />
of GRBs by GLAST that could make this diagnosis.<br />
15.7 Heavy numerical simulations<br />
The field of theoretical astrophysical dynamics has un<strong>de</strong>rgone two major evolutions in the last two <strong>de</strong>ca<strong>de</strong>s or<br />
so. First, the i<strong>de</strong>a that magnetic fields play a key role has progressively imposed itself to a community in which<br />
MHD phenomena had long been regar<strong>de</strong>d as exotic. Secondly, the progressive rise of powerful numerical tools<br />
(both software and hardware) has transformed numerical simulations from a gadget to a must in the exploration<br />
and un<strong>de</strong>rstanding of the nonlinear outcome of the physical processes consi<strong>de</strong>red as important in our tra<strong>de</strong>.<br />
Consequently, MHD has become the central area of study of accretion-ejection related phenomena, and the<br />
mo<strong>de</strong>rn dynamicist working in this field must not only master analytical techniques, but numerical ones as well.<br />
To a lesser but growing extent, a similar evolution can be witnessed in the field of high energy astrophysical<br />
processes, which is also of direct interest for the team activity.<br />
The French community is still largely lagging behind the international lea<strong>de</strong>rship on the numerical front, by<br />
lack of both human and material means (<strong>de</strong>spite the information ma<strong>de</strong> by the ASSNA). The SHERPA team<br />
has become more and more aware of this <strong>de</strong>ficiency for its own activity, and has therefore put a particular<br />
emphasis on numerics by progressively building up an internal expertise, and by <strong>de</strong>fining as a goal to address<br />
an evergrowing fraction of problems through (M)HD simulations (in support of more theoretical analyzes). In<br />
practice, this numerical activity is only now reaching a production stage, and has been un<strong>de</strong>rtaken in several<br />
directions:<br />
i- (M)HD stability and turbulent transport in disks and jets with Geoffroy Lesur (PhD started september<br />
2004) and P.-Y. Longaretti.<br />
ii- 2D magnetospheric star/disk interaction with Nicolas Bessolaz (PhD started november 2004) and J.<br />
156
Ferreira, in collaboration with Rony Keppens (Netherlands) and J. Bouvier (FOST). The goals are to study<br />
first, the conditions leading to steady accretion funnels and second, the possibility to launch Reconnection<br />
X-winds as envisioned by Ferreira, Pelletier & Appl (2000, MNRAS, 312, 387).<br />
iii- 3D magnetospheric star/disk interaction with Claudio Zanni (post-doc starting Fall 2005) and J. Ferreira,<br />
in collaboration with Christian Fendt (Germany). C. Zanni will study the oblique rotator and try to relate the<br />
dynamical situation computed with current observational works carried out by the FOST team (C. Dougados,<br />
J. Bouvier and F. Ménard).<br />
15.8 Astrocladistics<br />
Imagined by Didier Fraix-Burnet in 2001, astrocladistics is a brand new approach toward establishing an evolutionary<br />
history of galaxies, from which a new classification might be <strong>de</strong>vised. This methodology, borrowed<br />
from phylogenetic systematics, a branch of evolutionary biology, is built on the original i<strong>de</strong>a that galaxy diversity,<br />
generated by their evolution, in particular through interactions, could be organized in a hierarchical<br />
manner. In a similar way as for living organisms, Didier Fraix-Burnet and two biologists (Philippe Choler and<br />
Emmanuel Douzery) have proposed to <strong>de</strong>pict ”parenthood” between galaxy classes on hierarchical trees called<br />
cladograms. The un<strong>de</strong>rlying notion of complexity for galaxies is thus introduced in extragalactic astrophysics.<br />
Up to now, astrocladistics has been successfully used for the first time on a sample of Dwarf Galaxies from the<br />
Local Group, then on two samples of simulated galaxies (GALICS database of Bruno Gui<strong>de</strong>rdoni et al., stage<br />
<strong>de</strong> DEA of Anne Verhamme), and currently on samples of galaxies from the Virgo cluster in collaboration with<br />
Emmanuel Davoust from the <strong>Laboratoire</strong> d’Astrophysique <strong>de</strong> Toulouse. We now un<strong>de</strong>rstand how the few hundreds<br />
of galaxies in our samples could have evolved and how much they ”resemble” each other and why. All this<br />
work has been orally presented at two international conferences (Fraix-Burnet et al 2003, Fraix-Burnet 2004),<br />
three papers have been submitted (two of which are now accepted) and two others are being written. Cladistics<br />
is probably unusual and may be even somewhat revolutionary for astrophysicists, but it is clear today that it<br />
brings several concepts and a formalism of major interest for the contemporaneous extragalactic astrophysics.<br />
15.9 Participation in large collaborations<br />
The SHERPA team has strong involvements in several big international projects: the ”JETSET” european<br />
network, several instrumental collaborations (AMBER, VITRUV, SIMBOL-X, GLAST, ECLAIRS) and the<br />
large HESS international collaboration. Moreover, it has strong links with the GdR PCHE and the national<br />
programs PNPS and PNG.<br />
Instruments in which LAOG is involved :<br />
• AMBER: Didier Fraix-Burnet is a member of the Science Group and is PI or coI of several Guaranteed<br />
Time proposals on AGNs.<br />
• VITRUV: P.-O. Petrucci and G. Henri are members of the Science Group of this second generation<br />
instrument for the VLTI.<br />
Other instruments and projects :<br />
• JETSET is an european ”Marie Curie” Research and Training Network gathering 11 european laboratories<br />
which has officially began the 1st of february 2005 and will run four years (http://www.jetsets.org).<br />
J. Ferreira is sharing with S. Massaglia (Italy) the management of the Work Program ”MHD mo<strong>de</strong>ls of<br />
Jets and Outflows”.<br />
• SIMBOL-X: P-.O. Petrucci is member of the Science Group of this hard X-ray (0.5-70 keV) instrument<br />
that should be launched around 2010.<br />
157
Table 15.2: Former PhD stu<strong>de</strong>nts of the SHERPA group.<br />
Name PhD thesis Current position<br />
Françoise Rosso 1994 teacher (classes préparatoires)<br />
Jonathan Ferreira 1994 assistant professor in the group<br />
Alexandre Marcowith 1996 CNRS position at CESR-Toulouse<br />
Pierre-Olivier Petrucci 1998 CNRS position in the group<br />
Nicolas Renaud 1999 teacher (classes préparatoires)<br />
Evy Kersalé 2000 postdoctoral position at Leeds-Cambridge<br />
Fabien Casse 2001 assistant professor at Paris VII<br />
Denis Gialis 2004 engineer at ONERA<br />
Ludovic Saugé 2004 postdoctoral position at IPN-Lyon<br />
• GLAST: the whole team is involved in the scientific support. With an overlap with the HESS window,<br />
this mission should provi<strong>de</strong> invaluable clues on compact objects and GRBs.<br />
• ECLAIRS: G. Henri and G. Pelletier are involved in the scientific support of this instrument with the<br />
goal of studying the prompt emission of GRBs.<br />
• HESS: G. Henri, G. Pelletier, P.-O. Petrucci are <strong>de</strong>eply involved in the HESS collaboration where they<br />
provi<strong>de</strong> a scientific support, especially for the interpretation of Blazar observations and multi-wavelength<br />
approaches. This Astroparticle experiment is very successful (cf. papers in Nature, Science...) and is<br />
opening a new window of astrophysics.<br />
15.10 Doctoral formation and Schools<br />
The SHERPA team is heavily involved in teaching activities through the presence of 3 teachers (out of 6<br />
permanent members), including 2 professors who have benefitted from a position at the prestigious Institut<br />
Universitaire <strong>de</strong> France. One of them, G. Henri, is the current director for the ”Master 2 Recherche Astrophysique<br />
et Milieux Dilués”, which is the pre-doctoral year before French thesis.<br />
The group has regularly formed PhD thesis stu<strong>de</strong>nts who found good aca<strong>de</strong>mic or industrial positions for<br />
most of them (see Table 2).<br />
Members of the team have also organized schools for researchers. G. Henri, G. Pelletier and F. Ménard<br />
(FOST) organized a school on ”Accretion disks, jets and high-energy phenomena in astrophysics” in 2002 at<br />
Les Houches. A JETSET school on ”MHD jet mo<strong>de</strong>ls and constraints”, to be held January 2006, is organized<br />
by J. Ferreira and C. Dougados (FOST).<br />
15.11 Scientific Highlights (2002-2005)<br />
• ”Transport of cosmic rays in chaotic magnetic fields”, Casse Fabien, Lemoine Martin, Pelletier Guy, 2002,<br />
Phys. Rev. D.<br />
The knowledge of the diffusion coefficients of cosmic rays is crucial for astrophysical applications and<br />
especially for astroparticle physics, both for mastering the cosmic ray propagation and the efficiency<br />
of Fermi acceleration. They have been computed with a Monte Carlo simulation as a function of the<br />
cosmic ray rigidity and the spectrum of the magnetic field (characterized by its in<strong>de</strong>x and its <strong>de</strong>gree of<br />
irregularities). The Bohm scaling, often assumed in astroparticle physics in the strong turbulence regime,<br />
has been ruled out. The scalings <strong>de</strong>rived for the pitch angle diffusion and for the parallel diffusion with<br />
the ”quasi-linear theory” are exten<strong>de</strong>d in an appropriate way in the strong turbulence regime. However<br />
the transverse diffusion coefficient follows a law which is nor Bohm nor quasi-linear, but a law that stems<br />
from the analysis of the spatial chaos of field lines. This result is important to estimate the confinement<br />
time of cosmic-rays in galaxies and in extragalactic jets.<br />
158
• “Particle Transport in Tangled Magnetic Fields and Fermi Acceleration at Relativistic Shocks”, Lemoine<br />
Martin, Pelletier Guy, 2003, ApJ, 589L.<br />
In Monte Carlo simulations, test particle trajectories are followed in a magnetic scattering medium in<br />
which a plane is moving at subrelativistic or relativistic speed. The conditional probabilities for a particle<br />
to come back to the plane after crossing as a function of the pitch angles have been computed. Then<br />
the amplification of the particle energy at each Fermi cycle (downstream-upstream-downstream) across a<br />
shock is calculated for arbitrary value of the shock speed. Thus the formation of the cosmic ray spectrum<br />
at a relativistic shock is <strong>de</strong>rived and the result displays that the first Fermi cycle produces a strong energy<br />
amplification by a factor on the or<strong>de</strong>r of the shock Lorentz factor to the square, whereas the other cycles<br />
amplify by a factor 2, as predicted by Achterberg and Gallant. The in<strong>de</strong>x is computed as a function of<br />
the shock Lorentz factor and the results are in excellent agreement with an analytical formula. A precise<br />
law for the acceleration time have also been obtained.<br />
• “Stationary Accretion Disks Launching Super-fast-magnetosonic Magnetohydrodynamic Jets”, Ferreira<br />
J., Casse F. 2004, ApJ, 601, L139<br />
This is the last paper in the series on Magnetized Accretion-Ejection Structures (MAES), which represents<br />
the only available self-consistent mo<strong>de</strong>l of a self-confined jet driven by an accretion disk (with the disk<br />
fully resolved), able to cross all three MHD critical points. Biases induced by the self-similarity contraints<br />
are discussed.<br />
• ”Physical interpretation of the NGC 7469 UV/X-ray variability”, Petrucci, P. O., Maraschi, L., Haardt,<br />
F., & Nandra, K. 2004, A&A, 413, 477<br />
Data fits, with a <strong>de</strong>tailed mo<strong>de</strong>l of comptonized spectra obtained from simultaneous UV and X observations<br />
of a Seyfert galaxy. These fits not only reproduce the spectral shape, but the source variability as well.<br />
They allow us to show that the data are consistent with a mo<strong>de</strong>l where all the accretion power is liberated<br />
in the corona (producing X-rays), while the UV emission comes from the reprocessing of the X-ray flow<br />
rather than from the energy dissipation in the disk. The observed variability is produced by a geometric<br />
modification of the corona.<br />
• “Astrocladistics: a phylogenetic analysis of galaxy evolution. I. Character evolutions and galaxy histories”,<br />
D. Fraix-Burnet, P. Choler, E. Douzery, A. Verhamme. 2005, accepted in Journal of Classification.<br />
This is a first paper in series; the method of astrocladistics is <strong>de</strong>scribed. It should allow us to establish a<br />
galaxy classificatoin based on physical criteria besi<strong>de</strong>s the galaxy morphology.<br />
• “On the Relevance of Subcritical Turbulence to Accretion Disk Transport”, Lesur, G., and Longaretti,<br />
P.-Y. 2005, accepted in A&A<br />
This paper solves a riddle dating back to the seventies, and which has given rise to an important controversy<br />
in the last ten years. Namely, it is shown that a linearly stable, keplerian hydrodynamic flow is in<strong>de</strong>ed<br />
turbulent through non linear mechanisms, but that this turbulence has a low efficiency in terms of angular<br />
momentum transport, with a Shakura-Sunyaev parameter α < 10 −5 . The discrepancy between numerical<br />
simulations and laboratory experiments is explained away.<br />
• ”The bulk Lorentz factor crisis of TeV Blazars: evi<strong>de</strong>nce for an inhomogeneous pile-up energy distribution”,<br />
Gilles Henri & Ludovic Saugé, 2005, accepted in ApJ<br />
It is shown that the Lorentz factors of Blazar jets, <strong>de</strong>duced from homogeneous SSC mo<strong>de</strong>ls, are contradicted<br />
by the source statisticsn which implies Lorentz factors of or<strong>de</strong>r 3, whereas homogeneous mo<strong>de</strong>ls<br />
require 50 or more. The only way out of this conundrum is to take the jet stratification into account,<br />
so that high energy photons are not produced in the same region as low energy ones. Observations then<br />
require mono-energetic distribution functions whereas most mo<strong>de</strong>ls make use of power-law distributions.<br />
In contradistinction with the dominant view, this work shows that (1) jets do not need to be highly relativistic,<br />
and (2) turbulence rather than shocks is at the origin of the production of high energy particles.<br />
159
Chapter 16<br />
Perspectives<br />
The distinctive feature of our group lies in its focus on physical processes rather than on specific astrophysical<br />
objects. This emphasis has proven to be very fruitful: it allows to make progress on problems that appear in very<br />
different astrophysical contexts (e.g. turbulence in accretion disks, accretion-ejection, non-thermal radiation<br />
from jets) as it relies on the strong theoretical background required to correctly interpret and un<strong>de</strong>rstand<br />
observations. This last goal is mainly achieved through collaborations with the FOST team and international<br />
observational groups. We want therefore to maintain this specificity within the LAOG.<br />
However, our common interest in specific processes, namely MHD flows (laminar and turbulent), anomalous<br />
transport, kinetic particle acceleration and high energy radiative processes, naturally pinpoints to one astrophysical<br />
context best suited for the <strong>de</strong>velopment and testing of our theories. Our future activity will thus be<br />
mainly <strong>de</strong>voted to the un<strong>de</strong>rstanding of the physics of Black Hole environments.<br />
The study of MHD accretion-ejection flows around a central object will follow two distinct directions. The<br />
first one is the analysis of the timing properties of compact objects : quasars and microquasars. As said<br />
previously, X-ray binaries provi<strong>de</strong> the best available constraints on the time evolution of accretion-ejection<br />
structures. This aspect involves first a strong collaboration between several members of our group. In<strong>de</strong>ed,<br />
within our ”two-flow” paradigm, flares are produced by a catastrophic pair creation that must have a feedback<br />
on the surrounding MHD jet. One long term goal is therefore to couple pair plasma creation and dynamics<br />
with MHD. The un<strong>de</strong>rstanding of these phenomena will then be exten<strong>de</strong>d to AGNs which exhibit also strong<br />
variability. The hiring of a young scientist involved in this difficult topic would be very valuable to reinforce<br />
this theoretical activity.<br />
The second direction of study is the investigation of the magnetic interaction between a magnetized central<br />
object and its accretion disk, with a focus on angular momentum transfer. This topic is naturally building<br />
strong links with the FOST team. The best observationally studied objects are the young stars but our work<br />
will also apply to cataclysmic variables and some neutron stars. Numerical simulations are most likely the only<br />
efficient tool to attack this critical problem. This work has already begun with one PhD thesis (N. Bessolaz)<br />
and a JETSET post-doc (C. Zanni) and will <strong>de</strong>finitely be continued by using the most recent available co<strong>de</strong>s.<br />
The recent recruitment of P. Varnière within our group and her strong implication in the <strong>de</strong>velopment of the<br />
MHD version of the AstroBear co<strong>de</strong> is an invaluable input. Although a simultaneous treatment of both the<br />
local and global physics is still out of reach of the current large scale computer resources, we nevertheless hope<br />
to incorporate future results from MHD local analyzes as sub-grid constraints. On the longer term, we will<br />
simulate the environment of a rotating black hole, surroun<strong>de</strong>d by an accretion-ejection structure.<br />
The issue of turbulent transport in accretion disks is of major importance in astrophysics, with several open<br />
issues and controversies. One of them, the role of hydrodynamic nonlinear instabilities, has recently been resolved<br />
by our group, implying that purely hydrodynamic turbulent transport is most likely too inefficient. The<br />
source of transport therefore lies either in (magneto)hydrodynamic, 2D, wavelike structures, or in a local MHD<br />
instability driving turbulence, such as the magneto-rotational instability. In the latter case, the main difficulty<br />
and unsolved problem is the role of magnetic reconnection on the overall efficiency of the induced turbulent<br />
transport. No study has yet tackled this crucial issue, although numerical reconnection most probably largely<br />
160
controls the level of the anomalous transport observed in simulations. We plan to address the role of reconnection<br />
(non-relativistic and relativistic) in turbulent transport by means of numerical simulations in the Hall-MHD<br />
framework, following recent advances in the fusion context on this topic. This is a fundamental work that will<br />
have quite universal applications. Of course, this is a very difficult branch of numerical physics requiring more<br />
manpower than that currently available in the group, consi<strong>de</strong>ring international standards. Therefore, hiring a<br />
young researcher with a large expertise in both theoretical and numerical MHD is of primary importance in the<br />
mid-term, to keep up with international competition.<br />
Astrocladistics is now on the trails and two kinds of directions will be followed in parallel. The first one<br />
is the extension of its application to many more galaxies in the Universe. For instance, the integration of the<br />
Active Galactic Nuclei properties is a necessary and challenging task. In addition, with people in Toulouse, we<br />
are exploring higher redshift objects using big surveys in the making, like the Sloan Digital Sky Survey (SDSS).<br />
After this work (2006) we will strongly connect ourselves to the Virtual Observatory project which will probably<br />
be the i<strong>de</strong>al data base to feed astrocladistics analyses. The second direction of work is on the theoretical si<strong>de</strong>,<br />
particularly in collaboration with mathematicians in cladistics (statistics, classification, complexity), but also<br />
of course with astrophysicists specialized in galaxy physics and chemistry (interactions, stellar components,<br />
interstellar medium, gas and dust, etc...), as well as in cosmology (the very first objects of the Universe). A new<br />
taxonomy for galaxy classification will be proposed during the next few years (2007). It must be noted that<br />
cladistic analyses are heavily CPU <strong>de</strong>manding, and clusters and even grids of PCs are necessary to perform the<br />
calculations. A thesis subject (astrophysics) and a post-doc profile (cladistics/mathematics) will be proposed<br />
in 2006.<br />
Although mainly <strong>de</strong>voted to theoretical works, the SHERPA group has also been involved in many instrumental<br />
collaborations, and intends to strengthen and <strong>de</strong>velop this part of its activity, in the near, mid and long<br />
term projects. In the near future, it will actively initiate or collaborate to observing proposals with existing<br />
instruments : XMM, INTEGRAL, HESS. XMM and INTEGRAL are particularly valuable to study the high<br />
energy emission of compact objects, due to their excellent collection area, allowing fast temporal studies. The<br />
group has initiated in particular a new method to search for rapid QPOs in INTEGRAL data, allowing to<br />
extend their study at high energy (above 20 keV). Thanks to RXTE observations, these QPOs are well known<br />
to exist in galactic compact objects (X-ray binaries and micro quasars) at lower energy, but their spectrum<br />
is poorly known. A progress in this field could bring very strong constraints on the mechanism responsible<br />
for these oscillations, which is still a matter on intense <strong>de</strong>bate. The new analysis technique should be used in<br />
the next years to study archival data and initiate new proposals. The combination of XMM and INTEGRAL<br />
observations is also very valuable, and one of us (P.O. Petrucci) has already strong experience in this type of<br />
proposals. The collaboration with HESS, which the group is officially associated with, will of course continue.<br />
The rapid growth of <strong>de</strong>tected blazars will provi<strong>de</strong> numerous data of good quality, allowing <strong>de</strong>tailed comparisons<br />
with time <strong>de</strong>pendant simulations which have been <strong>de</strong>veloped in the group and will be improved in the next<br />
future by the inclusion of a better <strong>de</strong>scription of acceleration mechanisms (T. Boutelier’s thesis, starting in<br />
october 2005). Of course, the active participation to HESS shifts will go further.<br />
On a longer term, improvements of the existing instruments as well as the launching of new ones is expected.<br />
The HESS 2 project will increase significantly the collection area of the instrument, allowing a better sensitivity<br />
and the <strong>de</strong>tection of new objects, particularly TeV blazars. A very important application is the indirect<br />
measurement of Cosmic Infra Red Background (CIRB), which absorbs the TeV photons and increases the<br />
spectral in<strong>de</strong>x of a distant source. Another exciting discovery is the possible measurement of TeV emission<br />
from a micro-quasar, which would confirm the link between the physics of galactic black holes and extragalactic<br />
ones. The launching of GLAST, planned in 2007, is likely to open a new era in gamma-ray astronomy. Its<br />
unprece<strong>de</strong>nted sensitivity will allow to study a very large number of galactic and extragalactic objects in tha<br />
gamma ray range, bridging the current gap between INTEGRAL (below 1 MeV) and Atmospheric Cerenkov<br />
Telescopes (above 100 GeV). G. Pelletier and G. Henri are officially associated to the project as scientists.<br />
However, because of their teaching duties, the group will need to hire a new young researcher in or<strong>de</strong>r to<br />
maintain the reactivity <strong>de</strong>man<strong>de</strong>d by the scientific support of High Energy facilities (like HESS and GLAST).<br />
Because of its scientific position, the SHERPA group is also involved in two important intrumental projects<br />
that should be operative in the next <strong>de</strong>ca<strong>de</strong>. The first one is the SIMBOL-X hard X-ray mission, operating in<br />
the ∼0.5-70 keV range and with two or<strong>de</strong>rs of magnitu<strong>de</strong> improvement in angular resolution and sensitivity,<br />
which is proposed by a consortium of European laboratories (PI: P. Ferrando from Saclay). This will allow to<br />
elucidate outstanding questions in high energy astrophysics, related in particular to the physics of accretion<br />
onto compact objects, to the acceleration of particles to the highest energies, and to the nature of the Cosmic X-<br />
161
Ray background. The second project is VITRUV, a second generation VLTI instrument for aperture synthesis<br />
imaging with eight telescopes (PI: F. Malbet from LAOG). VITRUV will permit to obtain completely new<br />
results in a large numbers of astrophysical domains and in particular compact objects. Both projects are in<br />
a R&D level and we (mainly P.O. Petrucci and G. Henri) participate, since the beginning, to the scientific<br />
specification of both instruments.<br />
Other new <strong>de</strong>velopments will come from the contact with all the astroparticle facilities such as Pierre Auger<br />
Observatory, Neutrino Observatory (NET Cube), Gravitational Wave Observatories (VIRGO, LISA). Within<br />
10 to 15 years, we can reasonably expect that fascinating astrophysics <strong>de</strong>velopments will stem from correlating<br />
gamma-rays, neutrino and gravitational bursts from Black Hole environments. The AGNs containing double<br />
quasars are the most promising sources of gravitational waves for LISA.<br />
162
Part VII<br />
APPENDICES<br />
163
164
Chapter 17<br />
Appendix 1: General organization of<br />
LAOG<br />
17.1 Management structure<br />
The present management structure of LAOG has two levels, the Executive Committee [Comité <strong>de</strong> Direction]<br />
and the Advisory Board [Conseil <strong>de</strong> <strong>Laboratoire</strong>]. Their respective roles and composition are in part <strong>de</strong>fined<br />
by legal texts. They are <strong>de</strong>tailed in the LAOG internal by-laws [Règlement Intérieur], which were written<br />
after elaborate internal discussions involving the Advisory Board and an ad hoc working group, and have been<br />
officially approved by CNRS in 2005.<br />
In brief, the LAOG management structure is the following:<br />
Executive Committee<br />
The Executive Committe is in charge of running LAOG in all its aspects (scientific activities, human resources,<br />
administration and financial matters, safety, etc.). It meets on a weekly basis. Its composition (see the general<br />
organigram in Figure 1.3) of the Executive Summary is as follows.<br />
• Director (C. Perrier until Dec. 31, 2002, T. Montmerle thereafter)<br />
• Deputy Director (P.-Y. Longaretti until Aug. 30, 2003, J.-L. Monin thereafter)<br />
• Technical Director (P. Kern, since Sep. 30, 2002)<br />
• Head of Administration (F. Bouillet)<br />
• Computing Resources Manager (G. Duvert)<br />
Advisory Board<br />
The Advisory Board is composed of elected members and members nominated by the Director. Its composition<br />
reflects all personnel categories of LAOG. The key structure of LAOG (i.e., the four scientific teams and the<br />
technical group) is also represented. PhD stu<strong>de</strong>nts have two representaives, elected every year.<br />
The Advisory Board meets regularly, on average every two or three months, more often if necessary. Usual<br />
topics are: general organization, implications of scientific <strong>de</strong>cisions, priorities in hiring young researchers on<br />
permanent positions (in general, temporary collaborators like post-docs and visitors are selected after discussions<br />
between the four team lea<strong>de</strong>rs only), or any topic of general interest as proposed by any LAOG member. PhD<br />
stu<strong>de</strong>nt representatives do not participate in the discussions about priorities in hiring young researchers, but<br />
they participate in all the other meetings.<br />
In addition to the Director and Deputy Director, the current list of members is as follows.<br />
• Elected members<br />
165
– Ceccarelli Cecilia (AT)<br />
– Delfosse Xavier (AA)<br />
– Ferreira Jonathan (MC)<br />
– Malbet Fabien (CR)<br />
– Ménard François (CR)<br />
– Delboulbé Alain (IE)<br />
– Preis Olivier (IE)<br />
– Stadler Eric (IR)<br />
• Nominated members<br />
– Chelli Alain (AT)<br />
– Beust Hervé (AA)<br />
– Lefloch Bertrand (CR)<br />
– Bouillet Françoise (IE)<br />
– Freautrier Philippe (IR)<br />
– Kern Pierre (IR)<br />
17.2 Management tools and quality control<br />
In or<strong>de</strong>r to project an attractive image of its activities, LAOG has invested in refurbishing its web site:<br />
http://www-laog.obs.ujf-grenoble.fr through which all the main documents can be accessed, either publicly<br />
or internally. The activities of the teams are publicly available and regularly presented. A highlight window<br />
in the home page allows to directly browse through recent major results of LAOG, several of which having been<br />
the subject of press releases by our agencies (mainly CNRS and ESO).<br />
Also available via the LAOG web page is Symastro, an internal management system through which various<br />
documents (including instrumental projects), reports, minutes of meetings, electronic forms (or<strong>de</strong>rs, missions),<br />
etc., can be accessed using quality-control rules. Among the new documents is the “Règlement Intérieur” (LAOG<br />
by-laws), which regulates many aspects of the everyday life at LAOG (safety recommendations, working hours,<br />
composition of internal councils, etc.).<br />
166
Chapter 18<br />
Appendix 2: LAOG Technical group &<br />
facilities<br />
18.1 Introduction<br />
The organization LAOG technical group is driven by the necessity to support efficiently the activity of the<br />
astrophysical teams, mainly <strong>de</strong>dicated on three points:<br />
• general support to the laboratory (computing support);<br />
• R&D actions <strong>de</strong>dicated to the preparation of future operations;<br />
• direct involvements in the realization of large instruments <strong>de</strong>dicated to large international facilities and<br />
agencies (VLT-ESO, ESA, CNES, CFHT).<br />
The main drivers are the critical astrophysical requirements, which are mostly related to High Angular<br />
Resolution (HAR) observations for the two last above items.<br />
18.2 Teams<br />
The composition of the technical group aimes at having the full range of required specialties for all <strong>de</strong>sign studies<br />
of very specific instrument <strong>de</strong>dicated to HAR observations, either through adaptive optics or interferometry<br />
(mechanics, optics, electronics, instrument control, system engineering, project management, and software<br />
<strong>de</strong>velopment). An important part of the staff, 21 engineers and technicians, has a strong expertise for the<br />
<strong>de</strong>sign of the instruments main critical aspects.<br />
The technical group is thus organized into 5 teams (see organigram in Figure 1.3 )<br />
1. Instrumentation, including optics, tests and system expertise<br />
2. Electronics, including <strong>de</strong>sign, cabling, and system expertise<br />
3. Mechanics, with strong expertise in CAO, <strong>de</strong>tailed <strong>de</strong>sign, finite element analysis, MEMS/MOEMS <strong>de</strong>sign<br />
4. General support to the computing LAOG facilities<br />
5. Software <strong>de</strong>velopments for all instrumental projects.<br />
167
Among the various areas of expertise, very specific competences are available at LAOG, mainly related<br />
to micro-technologies. One concerns fiber optics and integrated optics conditioning, testing and operation for<br />
interferometry. The other one concerns adaptive optics mirror <strong>de</strong>sign and building.<br />
An important part of the software <strong>de</strong>velopment activity, oriented towards interferometry users, is related to<br />
the JMMC (Jean-Marie Mariotti Center, see GRIL chapter and next Appendix).<br />
18.3 Equipment<br />
The LAOG building contains specific facilities for technical <strong>de</strong>velopments and instrument integration activities.<br />
• Machine shop with required machining and metrology tools.<br />
• Working stations for CAO (mechanical <strong>de</strong>sign and finite element analysis together with related printing<br />
capabilities, thermal simulation, electronic <strong>de</strong>sign, optical <strong>de</strong>sign).<br />
• An optical lab <strong>de</strong>dicated to all Interferometry / Integrated Optics <strong>de</strong>velopments. It inclu<strong>de</strong>s:<br />
– facilities for gui<strong>de</strong>d optics characterization and connectorization.<br />
– An anti-vibration bench <strong>de</strong>voted to interferometric measurements related to the image reconstruction<br />
issues connected to the VITRUV <strong>de</strong>velopments,<br />
– An anti-vibration bench <strong>de</strong>voted to interferometric measurements related to thermal IR wave gui<strong>de</strong><br />
characterization.<br />
• A small clean room for <strong>de</strong>tector integrations, and micro-optics mounting.<br />
• An optical lab for adaptive optics <strong>de</strong>velopments, mainly for various Micro Deformable Mirrors characterization.<br />
• An electronic lab with all required tools<br />
• A 200 m 2 , 8-m high integration hall with related facilities (handling, fluid distribution capabilities, control<br />
rooms)<br />
• Vacuum room with all related equipment, including Helium leak <strong>de</strong>tector<br />
• Specific metrology equipments for component and instrument qualification (Wavefront Sensor , electronic<br />
auto pointing collimators, optical and mechanical displacement sensors)<br />
• Specific sources and <strong>de</strong>tectors for near and thermal infrared operations, and photometric characterization.<br />
Oncoming activities will require a significant evolution of the existing technical support. Due to the increasing<br />
range of activities but also to professional evolutions, it is already necessary to hire new engineers and<br />
technicians, specialists of adaptive optics system, of mechanical <strong>de</strong>sign and of software <strong>de</strong>velopment. It is also<br />
mandatory to improve the LAOG experimental integration facilities, especially to be able to achieve the VLT-PF<br />
and possibly VITRUV, integration phases in state-of-the-art conditions. One of the major foreseen improvements<br />
is the environmental control of the integration hall and of the optical lab. The strong constrains that<br />
apply to these sophisticated instruments are a major issue in or<strong>de</strong>r to meet the expected severe requirements.<br />
168
Chapter 19<br />
Appendix 3: International and Local &<br />
National responsibilities of LAOG<br />
members<br />
19.1 Responsabilités individuelles internationales<br />
19.1.1 Astromol<br />
Ceccarelli Cecilia Co-Astronomer du Consortium Heterodyne Instrument for the Far Infrared (HIFI), a bord<br />
du satellite ESA Herschel Space Observatory (HSO) (2000-2006)<br />
Coordinator du Group “HSO-HIFI Star Formation” (2001-2006)<br />
PI du Key Program HSO-HIFI “Line Surveys of Star Forming Regions” (2005-2006)<br />
Task Manager <strong>de</strong> “Chemistry in Star Formation” du resau EC FP6 “The Molecular Universe” (2005-2006)<br />
Kahane Claudine<br />
Prési<strong>de</strong>nte <strong>de</strong> la commission d’évaluation <strong>de</strong> lÕenseignement <strong>de</strong> la Physique dans les Universites belges francophones<br />
(jan 2003 - mai 2003).<br />
Montmerle Thierry<br />
Membre du Comité <strong>de</strong>s Programmes <strong>de</strong>s satellites XMM (ESA, 2005) et Chandra (NASA, 2002-2003)<br />
Membre du Comité <strong>de</strong>s Programmes <strong>de</strong> l’ESO, Prési<strong>de</strong>nt du Panel ”Star Formation” (2002-2005)<br />
Valiron Pierre<br />
Membre <strong>de</strong> l’Advisory Board <strong>de</strong> la revue Chemical Physics (-2006)<br />
19.1.2 FOST<br />
Jean-Charles Augereau:<br />
- membres <strong>de</strong>s groupes scientifiques <strong>de</strong>s instruments VLT/PF et VLTI/ApreS-MIDI<br />
Jérôme Bouvier:<br />
(2000-2004): CEE FP5 RTN (Clusters): <strong>Grenoble</strong> + 6 CEE institutes, co-PI<br />
(2002-2003): Key Program CFHT, 2002-2003 CFHT12K/MEGACAM, PI<br />
(2005-2006): ECO-NET 2005 : <strong>Grenoble</strong>-Tashkent-Moscou, PI<br />
(2001-2002): Membre extérieur du TAC du Telescopio Nazionale Galileo, Italie<br />
(2001): Membre Steering Committee CFHT-WIRCAM<br />
(2004): Membre du Groupe Scientifique CFHT-ESPADONS<br />
Catherine Dougados:<br />
(2005-2008): CEE FP6 RTN (JETSET): <strong>Grenoble</strong> + 10 CEE institutes, co-PI, Membre du comité exécutif <strong>de</strong><br />
JETSET (resp. du training et du suivi <strong>de</strong>s étudiants)<br />
Gilles Duvert:<br />
169
-responsable du groupe ”logiciel <strong>de</strong> traitement <strong>de</strong>s données AMBER”<br />
-Principal investigator du Work Package No2 du JRA4 du Reseau Europeen Opticon (OPTICON, WP2 JRA4)<br />
Nicolas Grosso:<br />
(2004): Membre du Target Allocation Committee <strong>de</strong> XMM-Newton pour l’ESA (A04)<br />
Fabien Malbet:<br />
(2001-présent): Membre du VLTI Science Demonstration Time<br />
(2001-2003): Membre du comité ad-hoc du VLTI Implementation Committee en charge <strong>de</strong> la prospective VLTI<br />
2005-2015<br />
- Project Scientist <strong>de</strong> l’instrument AMBER <strong>de</strong> L’ESO<br />
François Ménard:<br />
(2003-présent): membre du groupe scientifique du projet d’instrument VLT-PF <strong>de</strong> l’ESO<br />
Jean-Louis Monin:<br />
(2001-présent): membre du groupe scientifique <strong>de</strong> l’instrument AMBER<br />
19.1.3 GRIL<br />
Beuzit Jean-Luc<br />
Science Advisory Committee (SAC) du CFHT <strong>de</strong> 2000 a 2005<br />
responsable scientifique du JRA1 Opticon<br />
Chelli Alain<br />
5/ Coordinateur du JRA4 d’Opticon (”Integrating Interferometry into Mainstream Astronomy”)<br />
6/ Membre du bureau <strong>de</strong> l’Euro-Interferometry Initiative (EII)<br />
7/ Membre du bureau d’Opticon (ca ce n’est pas tres clair)<br />
8/ Responsable pour la partie francaise du projet ECOS M03U01 <strong>de</strong> collaboration avec le Mexique, Universite<br />
<strong>de</strong> Puebla (Interferometrie et Optique Adaptative)<br />
Duvert Gilles<br />
PI WP2 du JRA4<br />
Feautrier Philippe<br />
responsable du JRA2 dans le réseau Opticon<br />
Kern Pierre<br />
Membre du réseau Key Technologies <strong>de</strong> Opticon (préparation du FP6 et FP7)<br />
Le Coarer Etienne<br />
ELT <strong>de</strong>sign Studies (OPTICON) : EPICS<br />
Malbet Fabien<br />
Membre du VLTI Science Demonstration Time (2001-)<br />
Membre du comité ad-hoc du VLTI Implementation Committee en charge <strong>de</strong> la prospective VLTI 2005-2015<br />
(2001-2003)<br />
EuroWinter School, ”Observing with the VLTI” (mariotti.fr/obsvlti), Les Houches, 3-8 fevrier 2002<br />
JENAM’2002 workshop ”The VLTI Challenges for the Future”, Porto, 5-7 septembre 2002<br />
Perrier Christian<br />
terminé :<br />
Représentant francais à l’OPC ESO (2003-2004) (et membre d’un panel)<br />
En cours :<br />
CS European Interferometry Initiative (<strong>de</strong>puis 2003) (représentant francais)<br />
Zins Gérard<br />
OPTICON - Chef <strong>de</strong> projet JRA4<br />
EII - Membre du board<br />
19.1.4 SHERPA<br />
J. Ferreira<br />
Colea<strong>de</strong>r du work package ”MHD Mo<strong>de</strong>ls” du RTN JETSET<br />
G. Pelletier<br />
Membre <strong>de</strong> commissions <strong>de</strong> la collaboration HESS (group lea<strong>de</strong>rs, speaker bureau).<br />
170
19.2 Organisation <strong>de</strong> colloques, workshops et autres conférences<br />
19.2.1 FOST<br />
Jean-Charles Augereau:<br />
- Organisateur du 3eme atelier PNP/PNPS/PCMI: ”Formation <strong>de</strong>s Systèmes Stellaires et Planétaires”, tenu à<br />
CEA/Saclay, 26-27 mars 2002. (http://www-laog.obs.ujf-grenoble.fr/ augereau/ATELIER/ )<br />
- Organisateur du 4eme atelier PNP/PNPS/PCMI: ”Physico-chimie <strong>de</strong>s disques protoplanétaires et couplage<br />
grain/gaz”, LAM, 17-18 janvier 2005. (http://www.lam.oamp.fr/claire/atpcmi/atelierPCMI.htm)<br />
- membre du SOC <strong>de</strong> l’école du réseau européen PLANET: ”PLANET School and Network meeting: Spitzer’s<br />
View on Star and Planet Formation”, Lei<strong>de</strong>n, 14-18 Novembre 2005. (http://www.strw.lei<strong>de</strong>nuniv.nl/cms/web/2005/2005<br />
Jérôme Bouvier:<br />
Membre du SOC <strong>de</strong>s conférences suivantes:<br />
- Atelier PNPS/Journées SF2A 2002, Paris, Juin 02<br />
- Ecole Aussois, Oct. 2002: “Les Etoiles Massives: formation, structure, évolution”<br />
- Forum Quadriennal PNPS 2002, <strong>Grenoble</strong>, Oct.02<br />
- Ecole Aussois, Sept.05: ”Interactions dans les systemes composites: étoiles, disques et planètes”<br />
- Multiple Stars across the HRD, Jul.05, Garching<br />
- Protostars and Planets V, Hawaii, Nov.2005<br />
- Membre du LOC <strong>de</strong>s XXXIXth Rencontres <strong>de</strong> Moriond, ”Young Local Universe”, La Thuile, Aosta Valley,<br />
Italy, March 21 - 28, 2004.<br />
Almas Chalabaev:<br />
-XXXIXth Rencontres <strong>de</strong> Moriond, ”Young Local Universe”, La Thuile, Aosta Valley, Italy, March 21 - 28,<br />
2004. Membre du SOC, du LOC, et co-éditeur <strong>de</strong>s actes<br />
Catherine Dougados:<br />
- Co-organistrice <strong>de</strong> la première école du FP6-RTN JETSET, Villard <strong>de</strong> Lans, France, Janvier 2006.<br />
- Co-Organisatrice <strong>de</strong>s journées du LAOG 2003<br />
Gilles Duvert:<br />
(2002-présent): membre LOC <strong>de</strong> l’école ERCA (European Research Course on Atmospheres)<br />
Fabien Malbet:<br />
- EuroWinter School, ”Observing with the VLTI” (mariotti.fr/obsvlti), Les Houches, 3-8 février 2002<br />
- JENAM’2002, workshop ”The VLTI Challenges for the Future”, Porto, 5-7 septembre 2002<br />
- Journée PNP ”A la recherche du photon planétaire”, Semaine <strong>de</strong> la SFSA, Paris 28 juin 2002<br />
- Journée VLTI, Semaine <strong>de</strong> la SF2A 2004, Paris, le 17 juin 2004<br />
François Ménard:<br />
- Co-Organisateur <strong>de</strong> la session 78 <strong>de</strong>s écoles d’été <strong>de</strong>s Houches / NATO Advanced Study Institute: ”Accretion<br />
discs, jets, and High energy phenomena in astrophysics”, 29 juillet- 23 aout 2002, Les Houches, France.<br />
- Organisateur <strong>de</strong> l’atelier du Télescope Canada-France-Hawaii: ”PUEO NUI Science Case Workshop”, tenu à<br />
<strong>Grenoble</strong>, 22-23 Mai 2003.<br />
Jean-Louis Monin:<br />
- membre du SOC <strong>de</strong> la conférence ”IAC/TNG workshop on Ultra Low Mass Formation and Evolution”, La<br />
Palma, Espagne, 28 juin- 1 juillet 2005.<br />
19.3 Responsabilités individuelles locales et nationales<br />
19.3.1 Astromol<br />
Ceccarelli Cecilia<br />
Membre du Conseil Scientifique du LAOG (2003-2006)<br />
Coordinator du Group WAGOS (Working Astrophysics Group of Star Formation), financé par le Projet National<br />
PCMI (2002-2006)<br />
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Chef <strong>de</strong> l’ Equipe ASTROMOL du LAOG (2003-2006)<br />
Kahane Claudine<br />
Membre du Jury <strong>de</strong> concours <strong>de</strong> l’Agrégation <strong>de</strong> Physique (2000 a 2003).<br />
Directrice adjointe UFR <strong>de</strong> Physique UJF : <strong>de</strong> juillet 2000 a juillet 2002.<br />
CEVU UJF : membre élu <strong>de</strong>puis janvier 1998.<br />
Commission <strong>de</strong>s Finances UJF : membre élu <strong>de</strong>puis janvier 1998 (dont Prési<strong>de</strong>nte <strong>de</strong> 1998 a 2001).<br />
Directrice du Département Scientifique Universitaire UJF : <strong>de</strong>puis mai 2003.<br />
Bertrand Lefloch<br />
Membre du Conseil Scientifique du LAOG (2003-2006)<br />
Membre <strong>de</strong> la commission specialistes <strong>de</strong> Physique UJF <strong>de</strong>puis (2003-2006)<br />
Membre <strong>de</strong> la commission specialistes en section 34 <strong>de</strong> l’Universite <strong>de</strong> Provence Aix-Marseille (2003-2006)<br />
Membre du Conseil Scientifique du programme PCMI (2005-2006)<br />
Montmerle Thierry<br />
Direction du LAOG (2003 2006)<br />
Membre du Conseil Scientifique du Programme National ”Physique et Chimie du Milieu Interstellaire” (1996-<br />
2004)<br />
Membre du Conseil <strong>de</strong> la Société Francaise d’Astronomie et d’Astrophysique (1999-2003)<br />
(1998-2002) Responsable du segment ”Etoiles et galaxies” du CEA Valiron Pierre<br />
Membre élu au CS du département SdU et <strong>de</strong> l’INSU et participation á la CSA (2001-2005)<br />
Prési<strong>de</strong>nt du comité thématique “ Astrophysique, Géophysique, Terre soli<strong>de</strong>” pour les centres <strong>de</strong> calcul nationaux<br />
IDRIS et CINES (2000-2004)<br />
Membre du CS <strong>de</strong> l’ACI GRID (2002-2006)<br />
Membre du CS <strong>de</strong> l’Action Spécifique Observatoire Virtuel (ASOV) <strong>de</strong> l’INSU (2005-2006)<br />
Membre du CS <strong>de</strong> l’Action Spécifique Simulation Numérique en Astrophysique <strong>de</strong> l’INSU (-2006)<br />
Responsable <strong>de</strong>s moyens communs <strong>de</strong> calcul intensif <strong>de</strong> l’Observatoire <strong>de</strong>s Sciences <strong>de</strong> l’Univers <strong>de</strong> <strong>Grenoble</strong><br />
(-2006)<br />
19.3.2 FOST<br />
Herve Beust<br />
(2000-présent): Responsable <strong>de</strong> la coordination <strong>de</strong>s stages d’étudiants au LAOG<br />
(2003-présent): membre elu du conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
Jerome Bouvier:<br />
(1998-2002): Directeur du PN Physique Stellaire (PNPS)<br />
(1997-2003): Membre du CNAP (nommé)<br />
(2001-2003): Membre du Groupe ad’hoc Astrophysique du CNES<br />
(2001-2002): Membre <strong>de</strong> la CSE <strong>de</strong> l’UFR <strong>de</strong> Physique, UJF (nommé, <strong>de</strong>mission)<br />
(2002): Membre du Conseil <strong>de</strong> l’OSU du CRAL<br />
(1997-2003): Membre du Conseil <strong>de</strong> laboratoire du LAOG<br />
(1998-2003): Membre du TAC Télescopes Nationaux PNPS<br />
(2000-2002): Membre Groupe Prospective Spectroscopie Intégrale <strong>de</strong> Champ PNPS (chair)<br />
(2003): Membre du Comité d’Evaluation <strong>de</strong> l’IAP<br />
(2001-2004): Membre Groupe <strong>de</strong> Suivi Opération GI2T (chair)<br />
(2002-2004): Membre du Groupe <strong>de</strong> Suivi NARVAL/TBL<br />
(2005-présent): Membre CSD6 ANR ”Sciences <strong>de</strong> l’Univers et Géoenvironnement” (nommé)<br />
(1999-présent): Membre CSA INSU<br />
(2004-présent): Membre du Conseil <strong>de</strong> la SF2A<br />
(2003-présent): Représentant du LAOG au CNFA<br />
(2004-présent): Membre CSE Montpellier<br />
(2004-présent): Membre CSE Lyon<br />
Xavier Delfosse:<br />
(2003-présent): membre du conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
(2002-présent): prési<strong>de</strong>nt <strong>de</strong> la commission communication du LAOG<br />
(2002-présent): membre <strong>de</strong> la cellule communication <strong>de</strong> l’OSUG<br />
(2004-présent): membre du groupe scientifique <strong>de</strong> l’instrument OHP/SOPHIE<br />
Catherine Dougados:<br />
172
(2003-présent): Membre du CNAP, section astronomie. Membre du bureau, secrétaire<br />
(2004): Membre <strong>de</strong> la CSE <strong>de</strong> l’Observatoire <strong>de</strong> Paris<br />
(1999-2002): Membre du conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
Gilles Duvert:<br />
-Membre du conseil scientifique <strong>de</strong> l’action spécifique Observatoire Virtuel (AS OV)<br />
-Responsable <strong>de</strong> l’informatique du LAOG<br />
-Membre <strong>de</strong> la Commission Services Observation <strong>de</strong> l’OSUG<br />
-Membre <strong>de</strong> la Commission Services Communs <strong>de</strong> l’OSUG<br />
Anne-Marie Lagrange:<br />
(2002-présent): Directeur scientifique adjoint ”Astronomie-Astrophysique <strong>de</strong> l’INSU.<br />
Fabien Malbet:<br />
(2003-présent): Membre du Conseil Scientifique du Programme National <strong>de</strong> Physique Stellaire, Webmestre du<br />
site internet du PNPS<br />
(2004-présent): Membre du groupe d’expert exoplanètes pour la CSA<br />
(1999-2002): Animateur du Sujet Fléche ”exoplanètes” du Programme National <strong>de</strong> Planétologie<br />
(1999-présent): Membre du Conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
François Ménard:<br />
(1995-2004): Responsable scientifique du polarimètre STERENN du Pic-du-Midi<br />
(2001): membre <strong>de</strong> la CSE <strong>de</strong> l’UFR <strong>de</strong> Physique, UJF<br />
(2003-présent): membre du conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
(2002-2004): Membre du Groupe <strong>de</strong> Suivi NARVAL/TBL<br />
(2004): Membre du comité d’évaluation du GEPI<br />
(2004-présent): Membre (élu B1) <strong>de</strong> la section 17 du comité national du CNRS<br />
(2005): Membre du comité <strong>de</strong> revue du projet ELP-OA (représentant PNPS)<br />
(2004-2005): Membre du comité français d’allocation du temps <strong>de</strong> télescope du TCFH<br />
(2005-présent): Membre du Conseil <strong>de</strong> l’OSU du CRAL<br />
(2005): membre du comité d’évaluation du CRAL, représentant section 17<br />
(2002-présent): Responsable <strong>de</strong> l’équipe FOST du LAOG<br />
Jean-Louis Monin:<br />
(jusqu’en 1002) : Responsable du DEA ’Astrophysique et milieux dilués <strong>de</strong> l’UJF<br />
(2001-2002) : Directeur Scientifique MSU DS3 au ministère <strong>de</strong> la recherche<br />
(2004- présent) : Directeur adjoint du LAOG<br />
(2003- présent) : membre du CNU 34<br />
(2003-présent) : membre du CS <strong>de</strong> l’UFR <strong>de</strong> Physique<br />
(2002-présent): membre <strong>de</strong> la CSE à Besancon<br />
(2003-présent): membre <strong>de</strong> la CSE à Strasbourg<br />
19.3.3 GRIL<br />
Beuzit Jean-Luc<br />
Conseil National <strong>de</strong>s Astronomes et Physiciens (CNAP): 2004-2005<br />
P.I. du VLT-PF (instrument secon<strong>de</strong> generation ESO/VLT)<br />
Chelli Alain<br />
Membre du Conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG<br />
Directeur du JMMC<br />
Membre du Conseil Strategique HRA (cshra)<br />
Membre du bureau <strong>de</strong> la HRA<br />
Duvert Gilles<br />
Membre CS JMMC<br />
Membre CS AS Observatoire Virtuel<br />
Membre Nomme Commission Services Observation OSUG<br />
Membre élu Commission Services Communs OSUG<br />
directeur technique JMMC<br />
responsable logiciel traitement données AMBER<br />
Feautrier Philippe<br />
Trésorier Bureau du CAESUG<br />
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jury <strong>de</strong> concours:<br />
1 concours IR CNRS Meudon Bellevue en 2004<br />
1 concours IR CNRS <strong>Grenoble</strong> en 2005<br />
1 jury d’amnissibilité IR MEN Bap C en 2005<br />
Kern Pierre<br />
Membre du CS <strong>de</strong> l’ASHRA jusqu’en janvier 2005<br />
Membre du bureau <strong>de</strong> Alpes Optique et Photonique jusqu’en 2004 (opticiens du sillon Alpin) (inclue l’organisation<br />
<strong>de</strong> congrès)<br />
Co-chef <strong>de</strong> projet AMBER<br />
Jury <strong>de</strong> concours IE et IR <strong>de</strong>s universités en qualité d’expert (1 à 2 fois par an)<br />
Commission paritaire OSUG<br />
Organisation <strong>de</strong> l’Ateliers <strong>de</strong> l’Optique en Astronomie (Atelier INSU) <strong>Grenoble</strong> du 5 au 7 mars 2001 (200 personnes<br />
, actes)<br />
Le Coarer Etienne<br />
commissions <strong>de</strong> l’université : conseil scientifique<br />
CAESUG : suppléant CA<br />
jury <strong>de</strong> concours : expert et prési<strong>de</strong>nt trois fois l’an<br />
Perrier Christian<br />
terminé:<br />
Direction du LAOG - UMR 5571 (jusqu’à fin 2002), a ce titre:<br />
Direction-adjointe <strong>de</strong> l’Observatoire <strong>de</strong>s sciences <strong>de</strong> l’univers <strong>de</strong> <strong>Grenoble</strong> (i<strong>de</strong>m)<br />
Membre es-qualité du CA <strong>de</strong> l’OSUG et <strong>de</strong> diverses commissions (i<strong>de</strong>m)<br />
et du Comité directeur d’AMBER (jusqu’en 2003)<br />
en cours:<br />
Responsabilité <strong>de</strong> l’équipe <strong>de</strong> recherche instrumentale du LAOG (<strong>de</strong>puis 2003)<br />
Prési<strong>de</strong>nt du CS <strong>de</strong> lÕASHRA (<strong>de</strong>puis début 2004)<br />
a ce titre: membre <strong>de</strong> ses conseils et membre <strong>de</strong> la CSA (<strong>de</strong>puis 2005)<br />
Membre <strong>de</strong>: CSSO <strong>de</strong> l’OHP (<strong>de</strong>puis 2003)<br />
CA <strong>de</strong> l’OSU Marseille-Provence (<strong>de</strong>puis 2004)<br />
Haut Conseil Scientifique <strong>de</strong> l’Observatoire <strong>de</strong> Paris (<strong>de</strong>puis 2003)<br />
Comité scientifique français <strong>de</strong> lÕESO (<strong>de</strong>puis 2003) et Comité francais <strong>de</strong> l’ESO (i<strong>de</strong>m)<br />
Malbet Fabien<br />
Membre du groupe d’expert exoplanetes pour le CSA (2004-)<br />
Membre du Conseil Scientifique du Programme National <strong>de</strong> Physique Stellaire (2003-)<br />
Journée PNP ”A la recherche du photon planetaire”, Seemaine <strong>de</strong> la SFSA, Paris 28 juin 2002<br />
Journée VLTI, Semaine <strong>de</strong> la SF2A, Paris, le 17 juin 2004<br />
Animateur du Sujet Fleche ”exoplanetes” au sein du Programme National <strong>de</strong> Planetologie (1999-2002)<br />
AMBER Project Scientist<br />
Membre du Conseil <strong>de</strong> <strong>Laboratoire</strong> du LAOG (1999-)<br />
Webmaster du site Internet du PNPS<br />
Perraut Karine<br />
Membre elue <strong>de</strong> la commission ”Services d’observation” <strong>de</strong> l’OSUG <strong>de</strong> 2000 a 2004<br />
Membre elue <strong>de</strong> la commission <strong>de</strong> specialistes <strong>de</strong> physique <strong>de</strong> l’UJF <strong>de</strong>puis 2004<br />
Zins Gérard<br />
JMMC - Membre du CS/Chef <strong>de</strong> projet<br />
19.3.4 SHERPA<br />
G. Henri:<br />
Responsable du DEA, puis <strong>de</strong> la spécialité du Master 2<br />
Recherche ”Astrophysique et Milieux Dilués” <strong>de</strong>puis 2002<br />
Membre élu du CA <strong>de</strong> l’UJF <strong>de</strong>puis octobre 2002.<br />
Membre <strong>de</strong>s CSE <strong>de</strong> Strasbourg en 2002-2003, <strong>de</strong>s CSE <strong>de</strong> l’ENS<br />
Lyon et <strong>de</strong> l’Observatoire <strong>de</strong> Lyon <strong>de</strong>puis 2004 Membre du bureau <strong>de</strong> l’UFR <strong>de</strong> physique, chargé <strong>de</strong>s relations<br />
avec les<br />
enseignants, <strong>de</strong>puis 2003.<br />
174
Membre du conseil scientifique du LPSC <strong>de</strong>puis 2003<br />
Membre du CNU 34 e section <strong>de</strong>puis 2002<br />
Représentant du CNU au conseil scientifique <strong>de</strong> l’INSU <strong>de</strong>puis 2002<br />
Membre <strong>de</strong> la commission <strong>de</strong>s post-docs CNRS <strong>de</strong> l’IN2P3 <strong>de</strong>puis 2004.<br />
J. Ferreira<br />
Membre nommé <strong>de</strong> la CSE <strong>de</strong> lyon<br />
G. Pelletier<br />
Direction <strong>de</strong> l’équipe SHERPA du LAOG.<br />
Prési<strong>de</strong>nt du conseil scientifique du laboratoire <strong>de</strong> Paris VII APC.<br />
Membre du conseil scientifique du <strong>Laboratoire</strong> Physique Théorique et Astroparticule et <strong>de</strong> Montpellier.<br />
Membre <strong>de</strong> la Commission <strong>de</strong> Spécialistes <strong>de</strong> Physique <strong>de</strong> l’UJF.<br />
Membre du Conseil Scientifique du GdR PCHE.<br />
Membre (jusqu’en 2004) du conseil scientifique <strong>de</strong> l’ENS Lyon.<br />
175
Chapter 20<br />
Appendix 4: The Jean Marie Mariotti<br />
Center<br />
For technical reasons, the JMMC report is written in French in this document. A translation in English should<br />
follow shortly.<br />
Au cours <strong>de</strong>s années 90, le Programme National <strong>de</strong> Haute Résolution Angulaire (PNHRA), et par la suite<br />
l’Action Spécifique Haute Résolution Angulaire (ASHRA), appuyés par le <strong>Laboratoire</strong> d’Astrophysique <strong>de</strong><br />
<strong>Grenoble</strong> et l’Observatoire <strong>de</strong> la Cote d’Azur ont promu la création d’un Centre d’Expertise en Interférométrie<br />
Optique. En septembre 2000, le Centre Jean-Marie Mariotti (JJMC) ou Centre Mariotti a été crée par l’INSU<br />
(voir l’organigramme 20.1).<br />
20.1 Mission<br />
La mission du JMMC est d’unir les compétences et <strong>de</strong> coordonner les efforts français en vue <strong>de</strong> l’exploitation<br />
optimale <strong>de</strong> l’interférométrie optique. Ses vocations sont <strong>de</strong> :<br />
• Développer, produire, documenter et maintenir les logiciels nécessaires à l’exploitation ainsi qu’au suivi<br />
<strong>de</strong>s nouveaux équipements, en particulier le VLTI.<br />
• Stimuler la formation académique.<br />
• Participer à la réflexion prospective autour <strong>de</strong>s nouveaux instruments.<br />
20.2 Structure<br />
Le JMMC est un réseau <strong>de</strong> 11 <strong>Laboratoire</strong>s français, assimilable à un laboratoire sans murs, doté d’un centre<br />
<strong>de</strong> réalisation logicielle localisé au LAOG, d’un conseil scientifique et d’un bureau exécutif. Les <strong>Laboratoire</strong>s<br />
partenaires du JMMC sont les suivants :<br />
• Département d’Astrophysique (Université <strong>de</strong> Nice-Sophia Antipolis, UNSA)<br />
• Département Fresnel (Observatoire <strong>de</strong> la Côte d’Azur, OCA)<br />
• IAS (Institut d’Astrophysique Spatiale, Orsay)<br />
• LAOG (<strong>Laboratoire</strong> d’Astrophysique <strong>de</strong> <strong>Grenoble</strong>)<br />
• LAT (Observatoire <strong>de</strong> Midi-Pyrénées)<br />
176
• LESIA (Observatoire <strong>de</strong> Paris-Meudon)<br />
• LISE (Observatoire <strong>de</strong> Haute Provence)<br />
• IRCOM (Université <strong>de</strong> Limoges)<br />
• Observatoire <strong>de</strong> Bor<strong>de</strong>aux<br />
• Observatoire <strong>de</strong> Lyon<br />
• ONERA (Châtillon)<br />
20.3 Statut<br />
En 2001, le JMMC a été inscrit par la CSA dans la liste <strong>de</strong>s centres nationaux et internationaux <strong>de</strong> traitement<br />
et d’archivage reconnus parmi les services d’observation <strong>de</strong> l’INSU. Depuis 2003, il est <strong>de</strong>venu le GdR # 2596<br />
du CNRS, ce qui lui assure un financement récurrent sur 4 ans.<br />
20.4 Budget<br />
Le budget annuel moyen du JMMC est <strong>de</strong> 50KE en provenance du CNRS, auxquels doivent s’ajouter 70KE en<br />
provenance <strong>de</strong> contrats européens. Il sert essentiellement à financer <strong>de</strong>s missions et <strong>de</strong>s CDD.<br />
20.5 Direction et personnel<br />
Depuis sa création, le centre Mariotti est piloté par son directeur Alain Chelli, et <strong>de</strong>puis 2003 par son directeur<br />
technique Gilles Duvert pour faire face a la complexité croissante <strong>de</strong>s taches <strong>de</strong> réalisation logicielle. Les personnels<br />
scientifiques, <strong>de</strong> l’ordre <strong>de</strong> 25 chercheurs (approximativement 4 hommes.an équivalent plein temps),<br />
évoluent dans son réseau <strong>de</strong> laboratoires. Les personnels techniques, 3 ingénieurs permanents et 1 CDD (tous<br />
ITA CNRS), sont pour l’ensemble regroupés dans le centre <strong>de</strong> réalisation logicielle. Trois astronomes effectuent<br />
actuellement leur tache <strong>de</strong> service au sein du JMMC, ce sont : Merieme Chadid (OCA), Gaspard Duchêne<br />
(LAOG) et Pierre Kervella (LESIA).<br />
20.6 Le centre <strong>de</strong> réalisation logicielle<br />
Le centre <strong>de</strong> realisation logicielle localise au LAOG est forme par 3 ingénieurs permanents : Gerard Zins (Project<br />
Manager), Laurence Gluck et Sylvain Lafrasse, et d’un CDD : Guillaume Mella.<br />
Les projets du centre sont essentiellement <strong>de</strong>s projets <strong>de</strong> réalisation d’” instruments logiciels ” mis en oeuvre,<br />
coordonnés, réalisés, distribués et maintenus par les personnels en son sein. Les réalisations s’effectuent<br />
dans un strict cadre projet sous la direction du chef <strong>de</strong> projet. Les produits logiciels du centre sont mis à la<br />
disposition <strong>de</strong> l’ensemble <strong>de</strong>s laboratoires <strong>de</strong> recherche en astrophysique français ainsi que <strong>de</strong> la communauté<br />
<strong>de</strong>s astronomes européens, soit par téléchargement, soit par la mise en place <strong>de</strong> services web. Le centre fournit<br />
aussi une assistance utilisateurs, <strong>de</strong>s didacticiels et <strong>de</strong>s serveurs <strong>de</strong> documentation. Il a mis en place, maintient<br />
et développe tous les services informatiques distribués reliés à la gestion et à la réalisation <strong>de</strong>s projets du JMMC<br />
et du projet européen OPTICON-JRA4 (voir http://mariotti.ujf-grenoble.fr et http://eii-jra4.ujf-grenoble.fr).<br />
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20.7 Production informatique<br />
¡¢£¤¥¢¦¢¡§¨©¤¡¢� ��£¡©¥¢�£�¨��� �¢�£¡¥¨������������ ����������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������ ��������������������������������������� ��������������������������������������� ������������������������������ ������������������������� ����������������������������������������������������� ����������������������������������������������������������������������������������������������<br />
Figure 20.1: Organigramme du JMMC<br />
• ASPRO : logiciel généraliste <strong>de</strong> préparation aux observations interférométriques.<br />
• ASPRO-VLTI : spécialisé dans la préparation <strong>de</strong>s observations pour les instruments AMBER et MIDI du<br />
VLTI, mis à jour chaque semestre en fonction <strong>de</strong>s appels d’offre et <strong>de</strong>s configurations proposées par l’ESO<br />
sur ces instruments. Voir http://mariotti.ujf-grenoble.fr/ aspro.<br />
• SearchCalib : logiciel ” Observatoire Virtuel ” <strong>de</strong> recherche d’étoiles <strong>de</strong> calibration pour les observations<br />
interférométriques optiques.<br />
• Logiciel FLUOR <strong>de</strong> réduction <strong>de</strong> données pour l’expérience FLUOR et les observations VLTI avec l’instrument<br />
VINCI (maintenance arrêtée).<br />
• Logiciel MIDI <strong>de</strong> réduction <strong>de</strong> données <strong>de</strong> l’instrument MIDI du VLTI.<br />
• Bibliothèque <strong>de</strong> modules pour la réalisation d’un logiciel d’interprétation <strong>de</strong> données interférométriques<br />
optiques (dans le cadre du projet européen OPTICON-JRA4)<br />
• Logiciel XMLGui, Client-Serveur d’interface graphique pour <strong>de</strong>s applications web.<br />
20.8 Organisation <strong>de</strong> services informatiques distribués<br />
• Serveur d’applications ASPRO et SearchCalib,<br />
• Serveur <strong>de</strong> téléchargement d’applications.<br />
• Serveur CVS et sauvegar<strong>de</strong>.<br />
• Serveur <strong>de</strong> documentation.<br />
• Serveurs WEB JMMC et JRA4.<br />
• Serveur <strong>de</strong> liste <strong>de</strong> diffusion.<br />
• Plateforme <strong>de</strong> travail collaboratif pour les équipes <strong>de</strong>s <strong>Laboratoire</strong>s partenaires du JMMC et les équipes<br />
européennes du projet OPTICON-JRA4.<br />
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20.9 Groupes <strong>de</strong> Recherche et Développement<br />
Le VLTI est pour l’instant un interféromètre unique dans le sens ou il est conçu comme un instrument <strong>de</strong><br />
service géré par l’ESO. N’importe quel astronome peut faire une <strong>de</strong>man<strong>de</strong> <strong>de</strong> temps avec le VLTI, observer<br />
comme astronome visiteur et traiter ses données avec les logiciels développés par les consortia ayant construit<br />
les instruments. Cependant, cela ne suffit pas pour faire du VLTI un réel instrument <strong>de</strong> service. Pour ce faire,<br />
il faut développer les logiciels pour :<br />
1. préparer les observations, c’est à dire examiner leur faisabilité,<br />
2. calibrer les observations, c’est à dire sélectionner <strong>de</strong>s calibrateurs,<br />
3. Interpréter, les observables interférométriques en terme <strong>de</strong> modèles simples,<br />
4. reconstruire si cela est possible, l ’image <strong>de</strong> l’objet.<br />
Pour répondre à ces besoins, le JMMC a crée 4 groupes <strong>de</strong> recherche et développement. L’objectif <strong>de</strong> chaque<br />
groupe est <strong>de</strong> fournir <strong>de</strong>s algorithmes, éventuellement <strong>de</strong>s logiciels prototypes, qui seront codés ou recodés par<br />
les ingénieurs du centre <strong>de</strong> réalisation, appuyés au cas par cas par <strong>de</strong>s ingénieurs <strong>de</strong>s laboratoires partenaires.<br />
• ASPRO (Responsable Gille Duvert, collaborations : LESIA, OCA): Ce logiciel simule les observations<br />
avec le VLTI (ainsi que d’autres interféromètres). Il permet à l’issue <strong>de</strong> l’observation simulée <strong>de</strong> calculer<br />
le rapport signal sur bruit sur les paramètres astrophysiques (diamètres, séparation, etc...) d’objets ou<br />
<strong>de</strong> collections d’objets simples. La première version d’ASPRO, téléchargeable <strong>de</strong>s pages web du JMMC,<br />
a été délivrée en 2002. La secon<strong>de</strong> version, module <strong>de</strong> recherche <strong>de</strong> calibrateurs inclus et pourvue d’une<br />
interface web, a été <strong>de</strong>livree en 2004. Chaque semestre, ASPRO-LIGHT, une version d’ASPRO adaptée<br />
aux instruments et aux configurations du VLTI proposées par l’ESO, est mis à la disposition <strong>de</strong>s utilisateurs.<br />
• SearchCalib (Responsable Daniel Bonneau : OCA, collaborations : CDS. LAOG, LESIA, LUAN) : Les<br />
observations interférométriques ont besoin d’être calibrées <strong>de</strong>s effets <strong>de</strong> l’atmosphère et <strong>de</strong> l’instrument.<br />
Le logiciel Searchcalib intégré dans ASPRO permet, en utilisant les avantages <strong>de</strong> l’observatoire virtuel,<br />
<strong>de</strong> trouver les calibrateurs (source ponctuelle ou <strong>de</strong> diamètre connu) les mieux adaptés à une observation<br />
donnée dans les domaines visible et infrarouge. Sa structure a été conçue avec l’objectif <strong>de</strong> créer un catalogue<br />
<strong>de</strong> calibrateurs dynamique par la consultation en temps réel <strong>de</strong>s catalogues <strong>de</strong> la base <strong>de</strong> données<br />
VisieR au CDS. La première version <strong>de</strong> SearchCalib pour objets brillant (K≤5) a été délivrée en 2004, le<br />
secon<strong>de</strong> version pour objets faibles (K≥5) est prévue pour 2006.<br />
• Mo<strong>de</strong>l Fitting (Responsable Isabelle Tallon-Bosc : CRAL, collaborations : LAOG, LUAN, OCA) :<br />
L’objectif <strong>de</strong> ce groupe est développer un logiciel permettant d’interpréter les observables interférométriques<br />
(visibilité, phase différentielle et clôture <strong>de</strong> phase) en termes <strong>de</strong> modèles géométriques simples combinables<br />
(disque uniforme, source multiple, enveloppe, etc...). Depuis 2004, l’activité <strong>de</strong> ce groupe est <strong>de</strong>venue le<br />
Work Package 2.3 ” Mo<strong>de</strong>l Fitting ” du projet européen OPTICON-JRA4 (voir les projets européens).<br />
Une première version <strong>de</strong> ce logiciel sera délivrée en 2006.<br />
• Image Reconstruction (Responsable Eric Thiebaut : CRAL, collaborateur : ONERA) : L’objectif <strong>de</strong> ce<br />
groupe est <strong>de</strong> fournir un logiciel <strong>de</strong> reconstruction d’images à partir <strong>de</strong> données interférométriques, adapté<br />
au petit nombre <strong>de</strong> télescopes du VLTI. Deux logiciels prototypes ont été développés et sont en cours <strong>de</strong><br />
test et <strong>de</strong> comparaison avec d’autres logiciels. Depuis 2004, l’activité <strong>de</strong> ce groupe fait partie du Work<br />
Package 2.5 ” Image Reconstruction ” du projet européen JRA4 (voir les projets européens). Une première<br />
version <strong>de</strong> ce logiciel sera délivrée en 2007.<br />
Pour tous ces logiciels, le JMMC a mis en place une assistance utilisateurs au niveau européen (Gaspard<br />
Duchene, Pierre Kervella/LESIA).<br />
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20.10 Formation <strong>de</strong>s utilisateurs<br />
La formation <strong>de</strong>s utilisateurs <strong>de</strong>s moyens interférométriques est une <strong>de</strong> nos missions. En février 2002 nous avons<br />
organisé une école européenne aux Houches ” Observing with the Very Large Telescope Interferometer ”, centrée<br />
sur la préparation <strong>de</strong>s observations avec le VLTI (responsable Fabien Malbet). Nous prévoyons d’organiser 2<br />
écoles en 2006 :<br />
• Une école française à Porquerolles pour les ITA (la <strong>de</strong>man<strong>de</strong> est forte) sur la haute résolution angulaire<br />
en astrophysique (responsable Denis Mourard, OCA).<br />
• Une école européenne aux Houches sur la préparation <strong>de</strong>s observations et les premiers résultats astrophysiques<br />
avec le VLTI (responsable Guy Perrin, LESIA). Cette école pourrait fusionner avec la première<br />
école du projet Marie Curie (4 écoles interférométriques européennes <strong>de</strong> 2006 à 2009, voir Chapitre 5).<br />
20.11 Conduite <strong>de</strong> projets européens<br />
En 2002, <strong>de</strong>s discussions ont débuté entre les 3 centres interférométriques européens, le JMMC pour la France,<br />
FRINGE pour l’Allemagne et NEVEC pour la Hollan<strong>de</strong> afin <strong>de</strong> promouvoir l’interférométrie et <strong>de</strong> contribuer<br />
à générer une vision européenne. Les discussions se sont vite élargies à douze pays (Allemagne, Autriche, Belgique,<br />
France, Hollan<strong>de</strong>, Hongrie, Israel, Italie, Pologne, Portugal, Royaume Unis, Republique Tcheque) ainsi<br />
qu’à l’ESA et l’ESO, et ont abouti à la création <strong>de</strong> l’Euro-Interférométrie Initiative (EII).<br />
20.12 L’Euro-Interferometry Initiative<br />
L’EII consiste en l’ensemble <strong>de</strong>s projets interférométriques développés dans un cadre européen. L’EII est dotée<br />
d’un bureau formé par l’union <strong>de</strong>s bureaux <strong>de</strong>s projets la composant (les représentants français au bureau <strong>de</strong> l’EII<br />
sont : Alain Chelli, Gilles Duvert, Denis Mourard/OCA, Romain Petrov/LUAN et Guy Perrin/LESIA) et d’un<br />
conseil scientifique présidé par Thomas Henning (Hei<strong>de</strong>lberg) et formé par les représentants <strong>de</strong> chacun <strong>de</strong>s pays<br />
(Christian Perrier pour la France). Les missions <strong>de</strong> ce conseil scientifique européen sont <strong>de</strong> maintenir et renforcer<br />
l’interférométrie européenne, intégrer <strong>de</strong> nouveau pays, favoriser la formation et l’échange <strong>de</strong> visiteurs et enfin<br />
générer une vision long terme. Ses règles <strong>de</strong> fonctionnement sont régies par un Memorandum of Un<strong>de</strong>rstanding<br />
(MoU) approuvé par les représentants <strong>de</strong> chaque pays. En 2004 <strong>de</strong>ux projets ont été proposés et acceptés<br />
dans le cadre <strong>de</strong> l’I3 européen OPTICON : le Joint Research Activity # 4 (JRA4) ” Integrating Interferometry<br />
into Mainstream Astronomy ” (centré sur le VLTI) coordonné par Alain Chelli, et le Network5 (centré sur<br />
l’échange <strong>de</strong> visiteurs et la prospective) coordonné par Andreas Quirrenbach (Lei<strong>de</strong>n). Pour compléter ce cadre,<br />
un projet Marie-Curie <strong>de</strong> 4 écoles européennes à forte composante interférométrique, coordonné par Paolo Garcia<br />
(Porto), vient récemment d’être accepté par l’Europe (voir 20.2 la structure <strong>de</strong> l’EII et ses liens avec le FP6).<br />
Le JRA4 ” Integrating Interferometry into Mainstream Astronomy ” (voir http://eii-jra4.ujf-grenoble.fr): Le<br />
JMMC a une part déterminante dans le JRA4. Ce projet, centré sur le VLTI, est l’un <strong>de</strong>s 6 JRA d’OPTICON.<br />
Il implique tous les pays participants <strong>de</strong> l’EII, l’ESA et l’ESO et regroupe plus d’une vingtaine <strong>de</strong> laboratoires.<br />
Il est doté d’un budget <strong>de</strong> 1 ME étalé sur 5 ans, dont 260KE pour la partie française, également repartis sur 2<br />
Work Packages. La structure du JRA4 est la suivante (voir la 20.3):<br />
• WP1.1 ” Concept to feasibility studies ” : Le WP1.1 est co-dirigé par Denis Mourard (OCA). Il a pour<br />
objectif <strong>de</strong> préparer la secon<strong>de</strong> génération d’instruments du VLTI et est divisé en 2 phases : une phase<br />
d’étu<strong>de</strong>s <strong>de</strong> concept suivie d’une phase d’étu<strong>de</strong>s <strong>de</strong> faisabilité. Les étu<strong>de</strong>s <strong>de</strong> concept ont pris fin en avril<br />
2005 et les résultats ont été présentés au workshop commun l’ESO et <strong>de</strong> l’EII ” The Power of Optical/IR<br />
Interferometry : Recent Scientific Results and Second Generation VLTI Instrumentation ” d’avril 2005<br />
à Garching. Elles regroupent 6 instruments : 2 recombinateurs visibles et 4 recombinateurs infrarouges.<br />
Dans sa résolution d’avril 2005, le conseil scientifique <strong>de</strong> l’EII a recommandé à l’ESO <strong>de</strong> démarrer 2 étu<strong>de</strong>s<br />
<strong>de</strong> phase A pour un imageur 4-6 télescopes et a classé en priorité les concepts APRES-MIDI (extension<br />
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¡ ¢£¤¥¦§¨¤¥©¢£�§¨�¤§��¤�§¥¢£�¤�¨¤��¥��¢�� ������� ���������������������������������������������������������� ������������������������������������� ���������������������������������� �������������� ����������������� ���Figure<br />
20.2: Structure <strong>de</strong> l’Euro-Interferometry Initiative<br />
<strong>de</strong> l’instrument 10µm MIDI <strong>de</strong> 2 à 4 voies, responsable Bruno Lopez/OCA) et l’instrument VITRUV<br />
(imageur 4-8 voies IR proche en optique intégrée, responsable Fabien Malbet). Les étu<strong>de</strong>s <strong>de</strong> faisabilité<br />
démarreront dès que le conseil <strong>de</strong> l’ESO aura sélectionné les instruments VLTI <strong>de</strong> secon<strong>de</strong> génération.<br />
• WP1.2 ” Co-phasing and Fringe Tracking ”: Le WP1.2 est dirigé par Mario Gai (Torino). Il a pour<br />
objectif d’optimiser les performances <strong>de</strong>s instruments <strong>de</strong> co-phasage. Pour ce faire, un groupe <strong>de</strong> travail<br />
européen a été formé et les taches ont été distribuées. Ce travail est en cours.<br />
• WP2 ” Off-line data reuction software ”: Le JMMC est maître d’oeuvre du WP2 (responsable : Gilles<br />
Duvert, Project Manager : Gerard Zins), la partie logicielle du JRA4. Ce projet fournira la communauté<br />
<strong>de</strong>s utilisateurs européens du VLTI et du LBT (Large Binocular Telescope) un logiciel d’ai<strong>de</strong> à<br />
l’interprétation <strong>de</strong>s observations interférométriques. Il a été divisé en 5 parties :<br />
– WP2.1 ” Management and user support ” : Responsable Gilles Duvert, Project Manager Gerard<br />
Zins. Création du site web du JRA4 avec tous les services <strong>de</strong> communication entre les groupes,<br />
documentation, rapports, etc... Un support utilisateur (Gaspard Duchêne, Pierre Kervella/LESIA a<br />
été mis en place.<br />
– WP2.2 ” Common software ”: Responsable Gilles Duvert, Project Manager Gerard Zins. Développement<br />
d’une librairie <strong>de</strong> base pour les processus <strong>de</strong> communication, manipulation d’erreurs, règles <strong>de</strong> programmation.<br />
L’écriture <strong>de</strong> la librairie est pratiquement terminée.<br />
– WP2.3 ” Mo<strong>de</strong>l Fitting ” : Responsable Isabelle Tallon-Bosc/CRAL, collaborations : LAOG, LUAN,<br />
OCA. Logiciel <strong>de</strong> modélisation <strong>de</strong>s observables interférométriques (voir la section la section ” Mo<strong>de</strong>l<br />
Fitting ” <strong>de</strong>s Groupes <strong>de</strong> Recherche et Développement). Une première version <strong>de</strong> ce logiciel sera<br />
délivrée en 2006.<br />
– WP2.4 ” Astrométrie ” : Responsables Didier Queloz (Observatoire <strong>de</strong> Geneve), Andreas Quirrenbach<br />
(Lei<strong>de</strong>n). Calcul <strong>de</strong> mouvements propres et <strong>de</strong> paramètres orbitaux <strong>de</strong> systèmes multiples,<br />
développement d’un traitement <strong>de</strong> données interactif pour l’instrument PRIMA. La première version<br />
<strong>de</strong> ce logiciel sera délivrée en 2007.<br />
– WP2.5 ” Image Reconstruction ” : L’objectif est <strong>de</strong> fournir à la communauté <strong>de</strong>ux logiciels <strong>de</strong><br />
reconstruction d’images pour le VLTI, l’un original développé par le CRAL et l’ONERA et l’autre<br />
adapté <strong>de</strong>s algorithmes radio par l’université <strong>de</strong> Grena<strong>de</strong>, ainsi qu’un logiciel dédié aux données du<br />
LBT développé par le MPIA et le MPIfR. Une première version <strong>de</strong> ces logiciels sera délivrée en 2007.<br />
181
20.13 Darwin<br />
¡¢£¤¥¦§¨©��¤¦ ���������������������� ��������������������������������������������������������� �������������������������� ������������������ �������������������������������������������������� ����������������������������������������������������������� �������������������������������������� ��������������������������������� ���������������������� �������������������<br />
����������<br />
Figure 20.3: Structure du JRA4<br />
Darwin est une mission <strong>de</strong> l’ESA, prévue pour après 2015, dont l’objectif ambitieux est <strong>de</strong> détecter <strong>de</strong>s traces<br />
<strong>de</strong> vie extraterrestre sur <strong>de</strong>s exo-planètes <strong>de</strong> type tellurique. C’est un interféromètre spatial à 3 telescopes<br />
fonctionnant à 10µm en mo<strong>de</strong> frange ” nulling ”. En 2004, le JMMC en collaboration avec Alcatel Space a<br />
remporté l’appel d’offre <strong>de</strong> l’ESA ” Reconstruction of Exo-Solar Properties ”, doté d’un budget <strong>de</strong> 190KE, dont<br />
80KE pour le JMMC. Il s’agit d’une étu<strong>de</strong> sur 18 mois visant à simuler les cibles (Origin) et à développer les<br />
algorithmes <strong>de</strong> détection et <strong>de</strong> caractérisation <strong>de</strong>s planètes à partir <strong>de</strong>s mesures <strong>de</strong> DARWIN. Le JMMC est<br />
responsable <strong>de</strong> la partie scientifique : responsable Eric Thiebaut/CRAL, collaborateurs : IAS, LUAN, ONERA.<br />
20.14 Relations avec l’ESO et le MSC<br />
Dès sa création, le centre Mariotti a cherché à établir un accord <strong>de</strong> collaboration avec l’ESO pour la fourniture<br />
<strong>de</strong> services informatiques. Les activités du JMMC ont été présentées aux responsables du VLTI, à la Directrice<br />
Générale lors <strong>de</strong> sa visite au LAOG, ainsi qu’au comité <strong>de</strong>s utilisateurs <strong>de</strong> l’ESO. A chaque fois, le JMMC a<br />
reçu un accueil très favorable, mais rien ne s’est concrétisé jusqu’à présent. Il est à noter toutefois que le moteur<br />
<strong>de</strong> calcul du logiciel <strong>de</strong> l’ESO <strong>de</strong> préparation <strong>de</strong>s observations avec le VLTI est basé sur celui d’ASPRO (lien<br />
sur le JMMC <strong>de</strong> la page web du VLTI). La situation pourrait évoluer avec les nouveaux responsables du VLTI<br />
qui ont officiellement exprimé le désir <strong>de</strong> visiter les 3 centres interférométriques européens (JMMC, FRINGE et<br />
NEVEC) pour étudier les possibles collaborations. La visite du responsable du VLTI au JMMC aura lieu le 20<br />
octobre prochain. A suivre ...<br />
Le Michelson Science Center (MSC, CalTech) est en charge <strong>de</strong> l’interféromètre Keck et à ce titre, il a les<br />
mêmes préoccupations logicielles et <strong>de</strong> formation que les centres interférométriques européens. Il existe aussi<br />
une forte tradition <strong>de</strong> collaboration entre les interférométristes français et leurs collègues américains du MSC.<br />
C’est donc naturellement, à la suite <strong>de</strong> visites réciproques <strong>de</strong> leurs responsables en 2004 et 2005, que le JMMC<br />
et le MSC ont manifesté leur désir <strong>de</strong> collaborer dans <strong>de</strong>s actions logicielles et <strong>de</strong> formation, et <strong>de</strong> faciliter<br />
l’échange <strong>de</strong> visiteurs. Pour initier la collaboration, il a été décidé d’appuyer 1 à 2 visiteurs par an dans chaque<br />
sens.<br />
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20.15 Prospective<br />
Le centre Mariotti continuera à assister les utilisateurs, ainsi qu’à maintenir et à mettre à jour les produits<br />
logiciels qu’il met à la disposition <strong>de</strong> la communauté. A titre d’exemple, il sera nécessaire d’adapter le logiciel<br />
<strong>de</strong> préparation <strong>de</strong>s observations aux nouvelles configurations du VLTI ainsi qu’aux instruments <strong>de</strong> secon<strong>de</strong><br />
génération et <strong>de</strong> fournir un logiciel <strong>de</strong> recherche <strong>de</strong> calibrateurs pour les objets faibles. Le logiciel européen est<br />
à l’heure actuelle un logiciel minimum, il faudra le compléter par d’autres fonctions comme la possibilité <strong>de</strong><br />
permettre à l’utilisateur d’utiliser ses propres modèles astrophysiques pour interpréter ses mesures.<br />
Le JMMC participera activement au développement du traitement <strong>de</strong>s données <strong>de</strong>s d’instruments <strong>de</strong> secon<strong>de</strong><br />
génération du VLTI, ainsi qu’aux simulations <strong>de</strong> leur capacité d’imagerie.<br />
Nous préparons 2 écoles interférométriques pour 2006 (une école pour les ITA et une école européenne) et<br />
nous serons fortement impliqués dans l’organisation <strong>de</strong>s 4 écoles européennes dans le cadre du projet Marie Curie.<br />
Avec l’ASHRA et nos collègues européens, nous commençons à préparer le prochain programme européen<br />
(FP7). Suite à <strong>de</strong>s discussions préliminaires au niveau français, nous pourrions proposer à nos partenaires<br />
européens un projet interférométrique ambitieux alliant le sol (VLTI, Antartique, post-VLTI, ...) et l’espace<br />
(Darwin). Le projet Darwin est une <strong>de</strong> nos priorité, nous comptons répondre aux appels d’offre <strong>de</strong> l’ESA concernant<br />
les développements logiciels associés.<br />
Au-<strong>de</strong>là <strong>de</strong>s aspects scientifiques, notre préoccupation actuelle est la pérennisation du centre Mariotti, en<br />
particulier <strong>de</strong> son centre <strong>de</strong> réalisation logicielle. Celui-ci <strong>de</strong>vrait déménager en 2007-2008 dans un nouveau<br />
bâtiment adjacent au LAOG (CERMO, action appuyée par l’UJF). Le GdR centre Mariotti prendra fin en<br />
2006, nous réfléchissons à la structure la mieux adaptée dans laquelle le JMMC pourra être renouvelé (GdR ou<br />
autre).<br />
183