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

BASECOL database hosted in Meudon to feed line data analysis requests with the latest data. Corresponding
simple and pedagogic VO services (e.g. at LVG level) will be developed for the non specialist user with error
bars and warnings.
1.6.2 Long-term strategic questions for LAOG
The world’s astronomical panorama is evolving fast, and long-term instrumental projects are already at the
discussion or even R&D stage. LAOG has already been contacted to participate in some of these projects.
The main challenge for LAOG is to keep in focus its scientific goals, and to give a weighted priority to its
participation to any long-term project depending on how these goals may be fulfilled. While, as we have seen
at length, LAOG has definite projects for the 2007-2010 time frame, it also has to consider them within a
longer-term perspective, out to 2015 or even beyond.
While the list of opportunities may evolve, and no definite decision can be taken now, the current strategic
issues under discussion at LAOG are the following.
• Extremely Large Telescopes. There are several studies around the world to dramatically increase
the size of current telescopes by use of segmented mirrors. ESO, for its part, is pushing the OWL
(“OverWhelmingly Large”) telescope project. The target diameter is 100m, but feasibility studies may
reduce it to 30m. Whereas cosmologists push towards the largest possible sizes in order to collect photons
from the youngest possible galaxies, recent studies seem to indicate that beyond a diameter of 30m no
significant gain (in terms of a sensitivity vs. contrast compromise) can be expected for exoplanet science.
However, should the larger size be decided, there are ideas (in particular within LAOG) to use selected
mirrors of an ELT to make up an interferometer within the telescope itself, with an unprecedented, almost
continuous coverage of the uv plane.
• Astronomy in Antarctica. The fact that the French-Italian Concordia scientific station has recently
been completed at Dome C has given a boost to astronomical projects in Antarctica. Located deep
within the Antarctic plateau, at 3200m altitude in a very dry and stable atmosphere, Concordia is able
to provide a permanent logistical support, even in winter, for a dozen scientists of all disciplines. LAOG
participates in a recently approved EC-funded “Large Infrastructure” FP6 project (ARENA, see above),
which aims at investigating in detail the feasibility of establishing a European astronomy facility, including
an interferometer, at Dome C. Up to now, LAOG is involved modestly, mostly for scientific support (for
instance, a question to address: is Dome C a better location than Paranal for star and planet formation
issues ?). The rumours according to which ESA is currently studying the idea of putting the GENIE pre-
Darwin nulling interferometer at Dome C rather than at Paranal, under an adapted form (ALLADIN),
may change the situation: in view of its current involvement in Darwin R&D studies (see below), LAOG
is ready to adopt the view that, in addition to doing its own science with it, an ALLADIN-type project
can indeed be an important step towards a major space interferometer like Darwin. This will however
require extra manpower not currently available.
• Going out to space ? Darwin. This is an ESA “Horizon 2000+” program cornerstone. It will not
fly before 2015. Its primary scientific goal is extremely ambitious and difficult: to find evidence for
extraterrestrial life by detecting ozone lines (the currently accepted major tracer of life) on Earth-like
planets. This will be done with a 4-spacecraft nulling space interferometer (3 independent telescopes and
a recombiner, the whole array being controlled by laser beams), i.e., blocking with an extreme efficiency
(contrast of ∼ 10 −9 ) the light of the central star. This is arguably a formidable technological and scientific
challenge. While LAOG does not yet have its own expertise in exoplanetary atmospheres (drawn elsewhere
from solar system planetary and brown dwarf atmospheres), it is clear that it already has a strong longterm
scientific interest in Darwin. It has already manifested this interest by participating to the scientific
group of “Pégase”, a Darwin precursor space interferometer proposed to CNES, currently in competition
for a pre-Phase A study. The ozone lines to be detected being in the mid-IR range, it is critical for Darwin
to be able to recombine beams in this wavelength range. The recent result obtained by LAOG, after several
years of research under ESA/CNES/industrial R&D contracts, to guide 10 µm waves for the first time,
represents a breakthrough towards building a recombiner for Darwin. LAOG is seriously considering
boosting these instrumental efforts and will have, in parallel, to develop collaborations and/or its own
scientific expertise in planetary atmospheres in the next decade, to be able to reap for itself the scientific
benefits of this exciting adventure. It is noteworthy that the present LPG prospective includes a new
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