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

• 12D-Surface of NH3 with H2
• Rotational excitation of NH2D, ND2H with H2
• Experimental measurement and theoretical predictions of cross-sections for NH2D + H2
• Surface of H2CO with H2 for excitation studies of HDCO / H2CO
In Task 2, “Chemistry in Regions of Star Formation”, one of us (CC) is the task manager of the network,
and we are also involved in Topic 2.2, “Nitrogen Chemistry as tracers of protostellar condensation” for milestone
2.2.7:
• Sticking and desorption processes in dark cloud/proto-stellar models: impact on gas abundances and
ionization state
Finally in Task 3, “Databases and Web interfaces”, we are involved in milestone 3.2:
• Simulation tool combining astrophysical models and molecular data bases to produce synthetic spectra
for comparison with observations
Obviously the fulfillment of our commitments in the Molecular Universe network constitutes a large fraction
of the prospective of the Astromol team until the end of 2008.
We also plan to extend our contributions to milestone 3.2 to applications related to the Virtual Universe.
In particular, as already previously explained, we plan to develop original services for coupling the VO grid
to computer grids, and thus facilitate the systematic exploration of astrophysical models on a wide range of
objects selected by the VO requests.
4.5 Cosmology: a new frontier for Astromol ?
Cold interstellar dust and cosmology have a large interplay in the millimetre electromagnetic spectrum. Synergy
between these two fundamental fields in astrophysics (one’s signal is the noise source of the other) is also found
in instrumental, observational and data reduction techniques.
In the star formation process, one of the main topics in astrophysics, dust is both acting in it and tracing
it. Acting in it, because dust can evacuate some of the gravitational energy in some phases of the pre-stellar
collapse and dust is strongly coupled with the interstellar molecular gas, a central topic of Astromol. Tracing
the star formation process, because modern instrumentation, basically cold bolometers in the (sub)millimetre
domain, allows us to map dust, hence gas, with an equivalent column density as low as 10 22 H m −2 .
In the course of the present activity period, F.-X. Désert continued working on bolometer developments
in preparation for the Archeops balloon mission, to study the submm emission of the whole sky, with two
main constituents: (i) a foreground galactic dust emission; (ii) a cosmological microwave background (CMB),
basically at 3 K but with minute dust emission fluctuations (∆T ∼ 10 −4 at a few 100 GHz) tracing the earliest
episodes of galaxy formation in the recombination era.
While was F.-X. Désert formally belonging to the Sherpa group in the previous LAOG structure, it became
evident from this work that he should eventually join the Astromol group, for at least two reasons. First,
while mainly devoted to comological objectives, the Archeops mission is also rich in galactic dust astrophysics
implications (Benoît et al. 2004), and more generally, on cosmic dust in a variety of environments (submm
excess in the CMB possibly caused by dust created and ionized by Population III stars: Elfgren & Désert 2004).
Second, the associated instrumental work on bolometers is also in the submm range, and prepares for the High
Frequency Instrument (HFI) on Planck i.e., the companion satellite to Herschel used by the Astromol group.
This instrument includes a dilution cooling system made in Grenoble (Air Liquide and CRTBT), allowing
to obtain high resolution all-sky maps of cold dust with unprecedented sensitivity. In collaboration with
CRTBT and LPSC in Grenoble, and with the whole Archeops team, we are completing the publication of
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