A Dual-Transition Survey of CO in the Coma Cluster of Galaxies

Open Access
Publisher Website
Google Scholar
Abstract
We present CO (1–0) and (2–1) observations of 33 galaxies in the Coma/Abell 1367 supercluster made with the IRAM 30 m telescope. In addition, we observed four of the galaxies with the 15 m JCMT, at CO (2–1). The indicative molecular gas mass correlates strongly with the dust mass, and a stronger relationship is seen between the far-infrared and CO surface brightnesses than between the simple luminosities. Comparison of CO (2–1) spectra from IRAM and JCMT allows an estimate of the size of the CO emission region, which varies between 10% and 100% of the size of the optical disk, contrary to earlier estimates that the CO is contained within the optical half-light radius. There is a slight suggestion that starburst galaxies have a lower ratio of brightness temperatures, Tb(2–1)/Tb(1–0), than other galaxies.