Erik Rosolowsky edited Correlations_of_these_macroscopic_properties__.tex  about 8 years ago

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Correlations of these macroscopic properties give clues to the nature of the molecular medium. We compare the properties of the molecular clouds to those seen in the Milky Way study of \citet[][;S87]{Solomon_1987} because that work measured GMC properties using similar techniques as we do here. In Figure \ref{larson_figure}, we correlate the GMC properties and compare the result to the trends seen in the S87 data. First, we see (panel a) that there is good agreement between the virial and luminous masses in these clouds, and this is seen throughout the system. We color each datum by the galactocentric radius to highlight the variation in cloud properties across the face of the disk. The most massive clouds are found in the center of the galaxy, but these extreme clouds still show good agreement between the two mass estimates. Both mass estimates will be subject to $\sim 0.3~\mathrm{ dex}$ uncertainties, but even in high quality data, there remains about 0.5 dex of scatter \cite{Heyer_2009}.   The radius-velocity dispersion plot (Figure \ref{larson_figure}b) shows the size-line width scalings in these clouds. The Milky Way relationship shows a good lower bound for the population, but there is significant scatter to higher line widths at a give radius. These offset clouds are found in the center of the galaxy, and are also associated with the higher mass clouds. Such objects are typically seen in molecule rich environments, where the surface densities of clouds increase signficantly \cite{Oka_2001}, \cite{Rosolowsky_2005},\cite{Heyer_2009},\cite{Leroy_2015}. significantly \cite{Oka_2001,Rosolowsky_2005},\cite{Heyer_2009},\cite{Leroy_2015}.  The figure shows that the objects we identify can be associated with Milky Way molecular clouds. They have comparable sizes and mass scales, and they show the same underlying