Molecular gas properties of galaxies: The SMA CO(2-1) B0DEGA legacy project

In the last two decades high resolution (< 5 arcsec) CO observations for ~ 150 galaxies have provided a wealth of information about the molecular gas morphologies in the circumnuclear regions. While in samples of 'normal' galaxies the molecular gas does not seem to peak toward the nuclear regions for about 50% of the galaxies, barred galaxies and mergers show larger concentrations. However, we do not exactly know from an observational point of view how the molecular gas properties of a galaxy evolve as a result of an interaction. Here we present the SMA CO(2-1) B0DEGA (Below 0 DEgree GAlaxies) legacy project in which we are imaging the CO(2-1) line of the circumnuclear regions (1 arcmin) of a large (~ 70) sample of nearby IR-bright spiral galaxies, likely interacting, and that still remained unexplored due to its location in the southern hemisphere. We find different molecular gas morphologies, such as rings, nuclear arms, nuclear bars and asymmetries. We find a centrally peaked concentration in about 85% of the galaxies with typical size scales of about 0.5 - 1 kpc. This might be related to perturbations produced by recent interactions.
Comment: 7 pages, 4 figures, talk presented at "Galaxies and their Masks", celebrating Ken Freeman's 70-th birthday, Sossusvlei, Namibia, April 2010. To be published by Springer, New York, editors D.L. Block, K.C. Freeman, & I. Puerari