Molecular Gas in the Disk of M 31

J. Braine (1, 2, 3) , N. Brouillet (1, 2, 3) , Fabrice Herpin (1, 2, 3) , S. Mülle , Nemesio Rodriguez‐fernandez (1, 2, 3)

1 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
2 OASU - Observatoire aquitain des sciences de l'univers
3 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]

We present a study of the molecular gas throughout the disk of M 31. From observations with the IRAM 30-m telescope in the HCN and HCO^+ lines we have deduced the distribution of the dense gas in the disk of the galaxy and its variation as a function of the galactocentric radius. We have focused on a segment of a spiral arm to compare ISM tracers (CO, H I), star formation tracers (Hα, 24 μm) and the [C II] line emission from ISO observations. [C II] emission is an excellent tracer of star formation and by comparison with photodissociation region models we have estimated the quantity of H I that is the product of H_2 dissociation.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]

J. Braine, N. Brouillet, Fabrice Herpin, S. Mülle, Nemesio Rodriguez‐fernandez. Molecular Gas in the Disk of M 31. Formation and Evolution of Galaxy Disks, Oct 2007, Rome, Italy. pp.51. ⟨hal-00401247⟩