The Equilibrium State of Molecular Regions in the Outer Galaxy

A summary of global properties and an evaluation of the equilibrium state of molecular regions in the outer Galaxy are presented from the decomposition of the FCRAO Outer Galaxy Survey and targeted 12CO and 13CO observations of four giant molecular cloud complexes. The ensemble of identified objects includes both small, isolated clouds and clumps within larger cloud complexes. 12CO velocity dispersions show little variation with cloud sizes for radii less than 10 pc. It is demonstrated that the internal motions of regions with molecular masses greater than 10**4 msuns are bound by self gravity, yet, the constituent clumps of cloud complexes and isolated molecular clouds with M < 10**3 msuns are not in self gravitational equilibrium. The required external pressures to maintain the equilibrium of this population are (1-2)x10**4 cm-3-K.Comment: To appear in ApJ, 32 pages, 13 figures, 2 table