Star formation scales and efficiency in Galactic spiral arms

Journal
Date Issued
2015
Author(s)
Eden, D. J.
•
Moore, T. J. T.
•
Urquhart, J. S.
•
•
Plume, R.
•
Rigby, A. J.
•
Thompson, M. A.
DOI
Description
The authors wish to thank the anonymous referee for comments that have improved the quality of the paper. This work is based in part on observations made with the Spitzer Space Telescope , which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This publication makes use of data products from the WISE , which is a joint project of the University of California, Los Angeles and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. DJE wishes to acknowledge an STFC PhD studentship for this work. This research has made use of NASA's Astrophysics Data System.
Abstract
We positionally match a sample of infrared-selected young stellar objects, identified by combining the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire, Wide-field Infrared Survey Explorer and Herschel Space Observatory Herschel infrared Galactic Plane Survey, to the dense clumps identified in the millimetre continuum by the Bolocam Galactic Plane Survey in two Galactic lines of sight centred towards l = 30° and 40°. We calculate the ratio of infrared luminosity, LIR, to the mass of the clump, Mclump, in a variety of Galactic environments and find it to be somewhat enhanced in spiral arms compared to the interarm regions when averaged over kiloparsec scales. We find no compelling evidence that these changes are due to the mechanical influence of the spiral arm on the star formation efficiency rather than, e.g. different gradients in the star formation rate due to patchy or intermittent star formation, or local variations that are not averaged out due to small source samples. The largest variation in LIR/Mclump is found in individual clump values, which follow a lognormal distribution and have a range of over three orders of magnitude. This spread is intrinsic as no dependence of LIR/Mclump with Mclump was found. No difference was found in the luminosity distribution of sources in the arm and interarm samples and a strong linear correlation was found between LIR and Mclump.
Volume
452
Issue
1
Start page
289
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.452..289E
Rights
open.access
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