The SMA CO(2-1) B0DEGA Legacy Project

Understanding the connection between detailed molecular gas properties, star formation, nuclear activity and environment in galaxies have so far lacked of statistical significance, specially due to the large number of internal variables driving secular evolution that have to be further combined with external effects.

We aim to build and analyze in a systematic way the largest high resolution CO(2-1) survey of nearby galaxies to date which, together with previously published CO data, will allow us to tackle these fundamental studies from a statistical perspective. Our main sample is composed of N = 120 galaxies with no previous high resolution molecular gas data, mostly due the lack of mm/submm interferometers in the southern hemisphere. However, these galaxies can be easily observed by SMA given its ability to go down to -45 degree.

This large sample will provide a statistical value to the study of the mechanisms bringing the molecular gas to the central hundreds of parsecs, their role in the occurrence of fuelling episodes linked to nuclear HII and/or AGN, as well as on the parameters determining the 2D distribution of SF laws. The role of the environment will be also analyzed using complementary HI data, in order to test the relation between interactions and an increased gas concentration in the circumnuclear regions inferred from our pilot study, and that may be related to subsequent episodes of nuclear starburst and nuclear activity. Furthermore, this program will bring a whole new sample of galaxies that could be studied more in detail during ALMA's Early Science.

In a pilot study we have succesfully detected CO(2-1) for 30 of these galaxies with the SMA.

DSS optical maps of the 30 galaxies in the B0DEGA sample. The F.O.V of the images is 220 arcsec. The boxes indicate the 66 arcsec F.O.V of the CO(2–1) maps. The horizontal segment on the left side of each plot represents a 5 kpc linear scale.

CO(2–1) distribution of the 30 galaxies in the B0DEGA sample. The F.OV. is 66 arcsec, sligthly larger than the 52 arcsec HPBW of SMA at 230 GHz. Color scale ranges from 1 sigma to the maximum. The horizontal segment on the left side of each plot represents a 1 kpc linear scale.