12CO J = 1 - 0 observations of the Circinus galaxy using the Mopra 22 M radio telescope

Abstract

The J = 1 - 0 rotational transition of carbon monoxide has been used to trace the molecular gas at five different positions in the Circinus galaxy using the Australia Telescope National Facility 22 m radio telescope at Mopra. The intensity profile of the central CO emission has a full width at half maximum of 550 pc. The 12CO (1 - 0) spectrum at the centre of the galaxy has an integrated temperature of 145 K km per sec, with components peaking at 0.62 K and ranging in velocity from 200 - 600 km per sec. The total mass of molecular gas in the Circinus galaxy, assuming the CO intensity profile of the galaxy is similar to the radio continuum, is estimated. This estimate, combined with previously published far infrared data, yields a value for the star forming efficiency.