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Description
This study presents a catalog of 8107 molecular clouds that covers the entire Galactic plane and includes 98% of the ^12^CO emission observed within b+/-5^{deg}^. The catalog was produced using a hierarchical cluster identification method applied to the result of a Gaussian decomposition of the Dame+ (2001ApJ...547..792D) data. The total H_2_ mass in the catalog is 1.2x10^9^M_{sun}_, in agreement with previous estimates. We find that 30% of the sight lines intersect only a single cloud, with another 25% intersecting only two clouds. The most probable cloud size is R~30pc. We find that M{propto}R^2.2+/-0.2^, with no correlation between the cloud surface density, {Sigma}, and R. In contrast with the general idea, we find a rather large range of values of {Sigma}, from 2 to 300M_{sun}_/pc^2^, and a systematic decrease with increasing Galactic radius, R_gal_. The cloud velocity dispersion and the normalization {sigma}_0_={sigma}_v_/R^1/2^ both decrease systematically with R_gal_. When studied over the whole Galactic disk, there is a large dispersion in the line width-size relation and a significantly better correlation between {sigma}_v_ and {Sigma}R. The normalization of this correlation is constant to better than a factor of two for R_gal_<20kpc. This relation is used to disentangle the ambiguity between near and far kinematic distances. We report a strong variation of the turbulent energy injection rate. In the outer Galaxy it may be maintained by accretion through the disk and/or onto the clouds, but neither source can drive the 100 times higher cloud-averaged injection rate in the inner Galaxy.
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