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Excitation of turbulence by Cosmic Rays upstream a shock and consequences for the transport and the Fermi acceleration. The results we obtained on the transport of Cosmic Rays make its dependence on the MHD turbulence spectrum precise. There exist semi-phenomenological theories of inertial turbulence spectra for common situations where the turbulence is excited at large scales and then cascades over several decades towards smaller scales where the dissipation takes place. Moreover the Reynolds numbers in astrophysical media are very large. However, the turbulence excited upstream astrophysical shocks is of a particular nature. Indeed it is excited by an instability resulting from the acceleration of Cosmic Rays at the shock and the instability amplifies the MHD modes over all scales through a resonnant regime (larger scales) and a non-resonnant regime (shorter scales). We have thus undergone the calculation of the turbulence spectra and the transport coefficients. Then we examined the consequences of the excitation of MHD turbulence on the energetic balance and the final spectrum of the Cosmic Rays that is steepened. This theoretical effort was made necessary by the indications delivered by the new observations of supernovae remnants by Chandra and XMM. Our theory incorporates not only the newest developments on anisotropic MHD turbulence but also an important effect: the backscattering of progressive Alfvén modes off sound waves (more precisely the slow magneto-sonic waves). These studies have been realized with Martin Lemoine, Alexandre Marcowith (CESR) and G.P. (in course of publication). High energy emission and Cosmic Rays from Gamma-Ray Bursts Gamma-Ray Bursts (GRBs) are phenomena radiating as much energy as supernovae but in a very short time, a few seconds or even less. The collimation of the ultra relativistic flows involved in GRBs strongly amplifies the energy flux. Under the less favorable hypothesis about the magnetic field and its irregularities, it has been shown that Cosmic Rays undergoing scattering off relativistic magnetized fronts (revealed by the light curves) could indeed reach the UHE range (Gialis & Pelletier 2004). The performances of GRBs as sources of high energy radiation in the form of photons and neutrinos have been estimated (Gialis & Pelletier 2005). A gamma diagnosis of UHECR generation is proposed; the diagnosis in the range of a few tens of GeV appears to be non-ambiguous, because this signal of hadronic origin should not be contaminated by inverse Compton emission by electrons which is deeply in the Klein-Nishina regime. We are eagerly waiting for the observations of GRBs by GLAST that could make this diagnosis. 15.7 Heavy numerical simulations The field of theoretical astrophysical dynamics has undergone two major evolutions in the last two decades or so. First, the idea that magnetic fields play a key role has progressively imposed itself to a community in which MHD phenomena had long been regarded as exotic. Secondly, the progressive rise of powerful numerical tools (both software and hardware) has transformed numerical simulations from a gadget to a must in the exploration and understanding of the nonlinear outcome of the physical processes considered as important in our trade. Consequently, MHD has become the central area of study of accretion-ejection related phenomena, and the modern dynamicist working in this field must not only master analytical techniques, but numerical ones as well. To a lesser but growing extent, a similar evolution can be witnessed in the field of high energy astrophysical processes, which is also of direct interest for the team activity. The French community is still largely lagging behind the international leadership on the numerical front, by lack of both human and material means (despite the information made by the ASSNA). The SHERPA team has become more and more aware of this deficiency for its own activity, and has therefore put a particular emphasis on numerics by progressively building up an internal expertise, and by defining as a goal to address an evergrowing fraction of problems through (M)HD simulations (in support of more theoretical analyzes). In practice, this numerical activity is only now reaching a production stage, and has been undertaken in several directions: i- (M)HD stability and turbulent transport in disks and jets with Geoffroy Lesur (PhD started september 2004) and P.-Y. Longaretti. ii- 2D magnetospheric star/disk interaction with Nicolas Bessolaz (PhD started november 2004) and J. 156
Ferreira, in collaboration with Rony Keppens (Netherlands) and J. Bouvier (FOST). The goals are to study first, the conditions leading to steady accretion funnels and second, the possibility to launch Reconnection X-winds as envisioned by Ferreira, Pelletier & Appl (2000, MNRAS, 312, 387). iii- 3D magnetospheric star/disk interaction with Claudio Zanni (post-doc starting Fall 2005) and J. Ferreira, in collaboration with Christian Fendt (Germany). C. Zanni will study the oblique rotator and try to relate the dynamical situation computed with current observational works carried out by the FOST team (C. Dougados, J. Bouvier and F. Ménard). 15.8 Astrocladistics Imagined by Didier Fraix-Burnet in 2001, astrocladistics is a brand new approach toward establishing an evolutionary history of galaxies, from which a new classification might be devised. This methodology, borrowed from phylogenetic systematics, a branch of evolutionary biology, is built on the original idea that galaxy diversity, generated by their evolution, in particular through interactions, could be organized in a hierarchical manner. In a similar way as for living organisms, Didier Fraix-Burnet and two biologists (Philippe Choler and Emmanuel Douzery) have proposed to depict ”parenthood” between galaxy classes on hierarchical trees called cladograms. The underlying notion of complexity for galaxies is thus introduced in extragalactic astrophysics. Up to now, astrocladistics has been successfully used for the first time on a sample of Dwarf Galaxies from the Local Group, then on two samples of simulated galaxies (GALICS database of Bruno Guiderdoni et al., stage de DEA of Anne Verhamme), and currently on samples of galaxies from the Virgo cluster in collaboration with Emmanuel Davoust from the Laboratoire d’Astrophysique de Toulouse. We now understand how the few hundreds of galaxies in our samples could have evolved and how much they ”resemble” each other and why. All this work has been orally presented at two international conferences (Fraix-Burnet et al 2003, Fraix-Burnet 2004), three papers have been submitted (two of which are now accepted) and two others are being written. Cladistics is probably unusual and may be even somewhat revolutionary for astrophysicists, but it is clear today that it brings several concepts and a formalism of major interest for the contemporaneous extragalactic astrophysics. 15.9 Participation in large collaborations The SHERPA team has strong involvements in several big international projects: the ”JETSET” european network, several instrumental collaborations (AMBER, VITRUV, SIMBOL-X, GLAST, ECLAIRS) and the large HESS international collaboration. Moreover, it has strong links with the GdR PCHE and the national programs PNPS and PNG. Instruments in which LAOG is involved : • AMBER: Didier Fraix-Burnet is a member of the Science Group and is PI or coI of several Guaranteed Time proposals on AGNs. • VITRUV: P.-O. Petrucci and G. Henri are members of the Science Group of this second generation instrument for the VLTI. Other instruments and projects : • JETSET is an european ”Marie Curie” Research and Training Network gathering 11 european laboratories which has officially began the 1st of february 2005 and will run four years (http://www.jetsets.org). J. Ferreira is sharing with S. Massaglia (Italy) the management of the Work Program ”MHD models of Jets and Outflows”. • SIMBOL-X: P-.O. Petrucci is member of the Science Group of this hard X-ray (0.5-70 keV) instrument that should be launched around 2010. 157
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LABORATOIRE D’ASTROPHYSIQUE DE GR
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III Team ASTROMOL 41 2 Presentation
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8.1.3 Graduate Students . . . . . .
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VI Team SHERPA 145 15 Results 147 1
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Part I Foreword: Presentation of th
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Part II Executive Summary A 18th ce
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of CNRS for technicians and enginee
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Figure 1.3: New LAOG organigram (20
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heart attack. Manuel went back to t
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Figure 1.6: PhD student repartition
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• LAOG researchers (and publishin
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and published 95 papers in four yea
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• National astronomy programs. 4
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1.5 From dreams to reality: Human r
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and accretion disks with heavy nume
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emphasis on the chemistry of planet
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Part III TEAM ASTROMOL Sub-arcsecon
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• we develop quantum and classica
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Table shows not only the volume of
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• Herschel-HIFI: Astromol is invo
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particular, we calculated a 9D H2O-
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• The hot corinos. More spectacul
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the massive deeply embedded protost
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tens of visual magnitudes, hence pr
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quantum VCC-IOS approximation may f
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Rate constant (cm 3 s -1 ) 1e-09 1e
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• One of us (PV) is strongly invo
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sublimation of water ice trapped ei
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If the chemistry in the first phase
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4.2.2 Molecular Physics The theoret
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Source Herschel Time Astromol Class
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several important studies that anti
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Chapter 5 Selected Publications •
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Part IV TEAM FOST The first image o
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393254 (5MJup at 55 AU) & AB Pic (1
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2.2 µ m 0.5" 11.7 µ m Figure 6.1:
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Figure 6.3: Contribution of heating
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such mid-term (several weeks) magne
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systems: HD 141569, HD 32297, HD 18
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C2D Spitzer/IRAC and MIPS data of s
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et al. 2002; 2003). We have found t
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Figure 6.8: Distribution of separat
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with only three known to date. Most
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300 objects, a size sufficient for
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therefore no surprise that vast eff
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data to verify the predictions we a
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Chapter 8 Appendices 8.1 Members of
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