Galactic center molecular clouds. II - Distribution and kinematics

Abstract

The distribution and kinematics of the molecular gas near the Galactic center is discussed based on uniformly sampled molecular mapping data presented in a previous paper. It is found that the molecular gas in the inner 900 pc of the Galaxy is asymmetric in both space and velocity. Some of the gas lies out of the Galactic plane and must move in inclined orbits, but the bulk of the gas is in a thin layer in the Galactic plane. The gas near the Galactic center is highly turbulent. Internal velocity dispersions range from 15 to 50 km/s FWHM, a factor of 3-10 times higher than molecular clouds in the disk. Strong deviations from circular motion and the morphology of isolated features such as the l = 3 deg clouds suggest that much of the gas moves in elongated orbits. A new model is proposed for explaining the origin and energy source for the continuum and line-emitting radio filaments found near the Galactic center. 39 references.