A Uniform Catalog of Molecular Clouds in the Milky Way
  The all-Galaxy CO survey of Dame, Hartmann, & Thaddeus (2001) is by far the
most uniform, large-scale Galactic CO survey. Using a dendrogram-based
decomposition of this survey, we present a catalog of 1064 massive molecular
clouds throughout the Galactic plane. This catalog contains $2.5 \times 10^8$
solar masses, or $25^{+10.7}_{-5.8} \%$ of the Milky Way's estimated H$_2$
mass. We track clouds in some spiral arms through multiple quadrants. The power
index of Larson's first law, the size-linewidth relation, is consistent with
0.5 in all regions - possibly due to an observational bias - but clouds in the
inner Galaxy systematically have significantly (~ 30%) higher linewidths at a
given size, indicating that their linewidths are set in part by Galactic
environment. The mass functions of clouds in the inner Galaxy versus the outer
Galaxy are both qualitatively and quantitatively distinct. The inner Galaxy
mass spectrum is best described by a truncated power-law with a power index of
$\gamma=-1.6\pm0.1$ and an upper truncation mass $M_0 = (1.0 \pm 0.2) \times
10^7 M_\odot$, while the outer Galaxy mass spectrum is better described by a
non-truncating power law with $\gamma=-2.2\pm0.1$ and an upper mass $M_0 = (1.5
\pm 0.5) \times 10^6 M_\odot$, indicating that the inner Galaxy is able to form
and host substantially more massive GMCs than the outer Galaxy. Additionally,
we have simulated how the Milky Way would appear in CO from extragalactic
perspectives, for comparison with CO maps of other galaxies.
