Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble

laboratories of OSUG, a collaboration has grown up between LAOG and LGGE (H. Gallee) on the climate
modelling in Antarctica to model astronomical seeing, demonstrating the importance of the boundary layer
in Antarctica, of the order of 20-30 m high. The result is that seeing above this layer is exceptionally good
almost like space conditions, but at the ground level it is rather similar to other sites. Work has started
to use these results to predict performances of future instruments in Antarctica thanks to the experience
developed at LAOG for the AMBER instrument. Preparatory activities in view of astronomical use of the
Dome C Site in Antarctica have been largely reinforced early 2005 with various medium-size equipment
funding requests (to INSU/CSA and/or to IPEV) by several French laboratories and a European FP6
funding request led by N. Epchtein (LUAN), aiming at promoting first level studies of astronomical use
of the Dome C, whose funding would cover the period 2006-2007 and whose rationale must also be found
in the preparation of a large scale FP7 proposal.
In this context, LAOG is involved in the FP6 request at a limited level (6 men-months with 4 involved
persons) with the aim to participate in the definition of the astronomical goals and the studies of the
instrumental optimization for the Antarctica environment. We intend in particular to bring our expertise
in integrated optics interferometric recombiners and in interferometry at a system level.
In parallel, the LAOG may wish to look into the potentially major interest that GENIE, or an other
nulling instrument like ALLADIN, be installed at Dome C rather than on the VLTI and the compared
figures of merit to install 8m-type telescopes at Dome C as an alternative to ELTs on standard sites. We
intend to participate in the conceptual studies on which future decisions will have to be based.
12.2.2 Software development for interferometry
JMMC and European networks The detailed objectives of JMMC for this period will be described in
the report and request for renewal that will be prepared by the JMMC as a CNRS GdR (their preliminary
presentation is given in Appendix 2). We describe here how we feel, at LAOG, the orientation of the JMMC
should be for the next years.
The JMMC is currently heavily loaded by the tasks assigned by its council to which its participation, as a
major actor, to the Opticon JRA4 has added further pressure in 2004. Its present main guideline is to develop
software for the end Users of interferometry. The scheduled tasks include the development of software specific
to the optimized use of AMBER and it can be anticipated that the JMMC will try to cover the new needs
induced by the forthcoming installation of VITRUV-type (i.e. imagers) instruments on the VLTI. Moreover,
optical interferometry already joined other observational techniques in the more general framework of virtual
astronomical observatories, bringing some more constraints to the work load of JMMC.
In the future, the development of JMMC should be pursued with in mind an easy access to interferometric data
by the general astronomers both for preparing observations and for reducing them or access to science archives.
In this respect, a major outcome of JMMC is the possibility to produce and offer an image reconstruction
software optimized for aperture synthesis by optical interferometry. With all these undertakings, the JMMC is
very likely to be continued by CNRS for at least the length of the new ”quadrennial contract”.
In the longer term, it must be added that it could be beneficial to the community that the JMMC extend its
activities (services and support) to the larger domain of all high angular resolution techniques i.e. including the
specific AO data expected with ELTs.
12.2.3 R&D activities
PRIORITIES
Advanced IO components development In the domain of near-IR IO, the basic recombining functionalities
are now rather well mastered at least for 3 telescopes recombination. Future progress will come from
more functionally complex components, i.e. allowing recombination of more than 3 beams, or providing not yet
integrated functions like fringe tracking, achromatic phase shift or active functions (e.g. OPD scanning). Such
components would further strengthen the advantages of IO-based interferometric benches, therefore decrease
the overall system costs, a particularly interesting prospect for space applications.
As we did before with IOTA, we intend to test the components previously characterized in the laboratory on
the CHARA interferometer (Georgia State University) whose size and access are more adapted to this goal than
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