Millimeter interferometry of the molecular gas in ARP 20

The Owens Valley Millimeter Wave Interferometer has been used to map the 2.6-mm CO emission in the ultraluminous infrared galaxy Arp 220. Approximately 70 percent of the CO emission from the galaxy originates from an unresolved region less than 4 arcsec x 6 arcsec in size (corresponding to 1500 pc diameter) centered on the near-infrared nucleus. The mass of gas within this region is 10 to the 10th solar mass, which is about 30 times greater than that in an equivalent area of the Galaxy. This concentration could result in efficient star formation via cloud-cloud collisions and provide a significant accretion flow onto a compact, central object. 24 references