Interferometric observations of three giant molecular clouds in M31

Abstract

One field in the northern spiral arm of M31 has been mapped at 11 x 6 arcsec resolution with the Berkeley-Illinois-Maryland Array. Three giant molecular clouds are detected in this field. The properties of the clouds, such as diameter, line width, and mass, are very similar to those of giant molecular clouds in the Galaxy and in M33, and are consistent with the size-line-width relation obtained for molecular clouds in those galaxies. The largest cloud has a mass of 7 x 10 exp 5 solar masses, 40 percent larger than the most massive cloud seen in a much larger survey of molecular clouds in M33. Thus, despite a low molecular gas surface density, the molecular interstellar medium of M31 appears capable of organizing itself into quite massive molecular clouds.