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Title: Whole-disk Sampling of Molecular Clouds in M83
Abstract We present a catalog of clouds identified from the12CO (1–0) data of M83, which was observed using the Atacama Large Millimeter/submillimeter Array with a spatial resolution of ∼46 pc and a mass sensitivity of ∼104M⊙(3σ). The almost full-disk coverage and high sensitivity of the data allowed us to sample 5724 molecular clouds with a median mass of ∼1.9 × 105M⊙, which is comparable to the most frequently sampled mass of giant molecular clouds by surveys in the Milky Way (MW). About 60% of the total CO luminosity in M83's disk arises from clouds more massive than 106M⊙. Such massive clouds comprise 16% of the total clouds in number and tend to concentrate toward the arm, bar, and center, while smaller clouds are more prevalent in interarm regions. Most >106M⊙clouds have peak brightness temperaturesTpeakabove 2 K with the current resolution. Comparing the observed cloud properties with the scaling relations determined by P. M. Solomon et al. (1987, hereafter S87),Tpeak> 2 K clouds follow the relations, butTpeak< 2 K clouds, which are dominant in number, deviate significantly. Without considering the effect of beam dilution, the deviations would suggest modestly high virial parameters (medianαvir∼ 2.7) and low surface mass densities (median Σ ∼ 22M⊙pc−2) for the entire cloud samples, which are similar to values found for the MW clouds by T. S. Rice et al. (2016) and M.-A Miville-Deschênes et al. (2017). However, once beam dilution is taken into account, the observedαvirand Σ for a majority of the clouds (mostlyTpeak<2 K) can be potentially explained with intrinsic Σ of ∼100M⊙pc−2andαvirof ∼1, which are similar to the clouds of S87.  more » « less
Award ID(s):
2006600
PAR ID:
10649851
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
976
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
198
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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