Gas phase elemental abundances in molecular clouds

Project overview
"Gas phase Elemental abundances in Molecular Clouds" (GEMS) is a IRAM Large Program granted with 458h of observing time in the 30m IRAM telescope.

The goal is ro determine the S, C, N, O depletions and X(e-) as a function of visual extinction, in a selected set of prototypical star forming filaments (TMC1, B213/L1495, Barnard 1, NGC 1333, IC348, L1448, B5, Orion A).
These parameters are the essential ingredients for chemical models and for cloud collapse simulations because they govern the gas cooling and the coupling of the gas with the magnetic field. Hence, they are of paramount importance for star formation galactic studies. From the chemical point of view, the variation of the elemental abundances in gas phase is a valuable information to determine the evolution of dust grains and the composition of the icy grain mantles across the cloud.
As an intermediate product, we will provide a complete set of molecular data in dark clouds.
In particular, our dataset will include high-sensitivity spectroscopic observations of CS, SO, H2S, HCS+, SO2, OCS and H2CS.
Up to our knowledge, it constitutes the best S-bearing molecules dataset in dark clouds so far, and a key stone to progress in our understanding of the sulfur chemistry.
GEMS Team Members
PI: Asución Fuente (  co-Is: Belén Tercero (, Barbara Giuliano (, Benoit Commercon (, Bertrand Lefloch (, Paola Caselli (, Derek Ward-Thompson (, Evelyne Roueff (, Rachel Friesen (, Maryvonne Gerin (, Álvaro Hacar (, Izaskun Jiménez-Serra (, Jacob Laas (, Jean Christophe Loison (, Jason Kirk (, José Cernicharo (, Jaime Pineda (, Javier R. Goicoechea (, Carsten Kramer (, Valerio Lattanzi (, Mario Tafalla (, Marcelino Agúndez (, Guillermo Muñoz-Caro (, Nuria Marcelino (, Octavio Roncero (, Pablo Riviere-Marichalar (, Pierre Gratier (, Johana Malinen (, Rafael Bachiller (, Rafael Martín-Doménech (, Santiago García-Burillo (, Sandra P. Treviño-Morales (, Tomás Alonso-Albi (, Thomas Vidal (, Valentine Wakelam (
More details
GEMS Team Organization
Work Packages Team Members
Obs & Data reduction A. Fuente, P.Riviere-Marichalar, B. Tercero, N. Marcelino, T. Alonso-Albi
Chemical modeling & RT V. Wakelam, J. Laas, P. Caselli, E. Roueff, J.C. Loison, V. Lattanzi, T. Vidal, M. Agúndez, I. Jiménez, B. Commercon, P. Gratier, J. Cernicharo
Laboratory & ab initio calculations G. M. Muñoz-Caro, V. Lattanzi, B.M. Giuliano, R. Martín-Doménech, O. Roncero
Complementary data J. Malinen, D. Ward-Thompson, J. Kirk, A. Hacar, J. Pineda, J. Cernicharo, M. Tafalla, R. Bachiller, B. Lefloch
Targets specilists, data interpretation & publication A. Fuente, M. Gerin, J.R. Goicoechea, R. Bachiller, J. Cernicharo, P. Caselli, A. Hacar, M. Tafalla, J. Pineda, S. García-Burillo, C. Kramer and all team