The Scale Height of Giant Molecular Clouds Is Less than That of Smaller Clouds

Abstract

An antenna temperature thresholding algorithm is used on the Bell Laboratories 13CO J = 1 → 0 Milky Way Survey to create a catalog of 1400 molecular clouds. Of these, 281 clouds are selected for having well-determined kinematic distances. The scale height, luminosity, internal velocity dispersion, and size of the cloud sample are analyzed to show that clouds smaller than ~105.5 M☉ have a scale height which is about 35 pc, roughly independent of cloud mass, while larger clouds, the giant molecular clouds, have a reduced scale height which declines with increasing cloud mass.