A UNIFORM CATALOG OF MOLECULAR CLOUDS IN THE MILKY WAY

Journal Article · Sun May 01 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/822/1/52· OSTI ID:22862973

Rice, Thomas S.; Bergin, Edwin A. ^[1]; Goodman, Alyssa A.; Dame, T. M. ^[2]; Beaumont, Christopher ^[3]

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1. Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Avenue, Ann Arbor, MI 48109 (United States)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. Counsyl, 180 Kimball Way, South San Francisco, CA 94080 (United States)

The all-Galaxy CO survey of Dame et al. 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 × 10{sup 8} solar masses, or 25{sub −5.8}{sup +10.7}% of the Milky Way's estimated H{sub 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 the 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 γ = −1.6 ± 0.1 and an upper truncation mass of M {sub 0} = (1.0 ± 0.2) × 10{sup 7} M {sub ⊙}, while the outer Galaxy mass spectrum is better described by a non-truncating power law with γ = −2.2 ± 0.1 and an upper mass of M {sub 0} = (1.5 ± 0.5) × 10{sup 6} M {sub ⊙}, 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.

• OSTI ID: 22862973
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 822; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CARBON MONOXIDE
CATALOGS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
GALAXIES
HYDROGEN
LINE WIDTHS
MASS
MASS SPECTRA
MILKY WAY
MOLECULES