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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 <sup>12</sup>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<sub>2</sub> mass in the catalog is 1.2 x 10<sup>9</sup> M<sub>sun</sub>, in agreement with previous estimates. The authors 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. In contrast with the general idea, the authors find a rather large range of values of surface densities, Sigma = 2 to 300 M<sub>sun</sub>/pc<sup>2</sup>, and a systematic decrease with increasing Galactic radius, R<sub>gal</sub>. The cloud velocity dispersion and the normalization sigma<sub>0</sub> = sigma<sub>v</sub> / R<sup>1/2</sup> both decrease systematically with R<sub>gal</sub>. 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<sub>v</sub> and SigmaR. The normalization of this correlation is constant to better than a factor of two for R<sub>gal</sub> < 20kpc. This relation is used to disentangle the ambiguity between near and far kinematic distances. The authors 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. The data set used in this catalog come from that of Dame+ (2001ApJ...547..792D). Those authors combined observations obtained over a period of 20 yr with two telescopes, one in the north (first located in New York City and then moved to Cambridge, Massachusetts) and one in the south (Cerro Tololo, Chile). These 1.2m telescopes have an angular resolution of ~8.5' at 115GHz, the frequency of the <sup>12</sup>CO 1-0 line. For the current study the authors used the data set covering the whole Galactic plane with +/- 5 deg in Galactic latitude. This table was created by the HEASARC in March 2019 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/834/57">CDS Catalog J/ApJ/834/57</a> file table1.dat. This is a service provided by NASA HEASARC .
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