About B0DEGA

We present the SMA B0DEGA (Below 0 DEgree GAlaxies) project, a high resolution (3 arcsec) survey of CO(2-1) (and isotopes) emission of the circumnuclear regions (1 arcmin) of 30 previously unexplored southern nearby galaxies obtained using the Submillimeter Array (SMA).

The main aim of the B0DEGA project is to investigate the fundamental properties of molecular gas in the circumnuclear regions and its relation with the environment, star formation and nuclear activity. The study that we present here is aimed at identifying the global distribution and the underlying symmetries of the structures of molecular gas.

The sample is composed of IR-bright galaxies (2.58 x S60 + S100 > 31.5 Jy) with recession velocities V < 7000 km/s. We focus on galaxies in the southern sky, where the lack of mm/submm interferometers has prevented to study with high resolution the molecular gas properties of many galaxies. We exploit SMA's unique ability to efficiently observe galaxies down to Dec. = -45 degrees.

The galaxies in the sample are part of likely interacting systems located in intermediate environmental densities. Most of the galaxies are found to be barred spiral galaxies, and although they have signs of interactions, they cannot be classified as major mergers. Our sample fills the gap of previous studies focusing on normal galaxies and on galaxy mergers. The targeted galaxies are characterized by distances 129.6 to 1011 Lsun and IR luminosities in the range 109.9 < LIR < 1011.3 Lsun.

The detection rate of our observations is 100%. We find total gas masses Mgas = 108 -1010.5 Msun. Our observations show that the molecular gas peak in 86% of the sample. It is remarkable that we find predominantly circumnuclear disks. The characteristic widths of such features are lower than 1 kpc for all the galaxies that peak at the center, and lower than 500 pc for about 50% of the sample. The galaxies that do not peak at the center show ring structures or nuclear bars with nuclear spiral arms emerging from it. More extended structures are also found, such as rings, larger scale arms as well as more extended disk structures.