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The effect of spiral arms on star formation in the Galaxy

Moore, TJT, Urquhart, JS, Morgan, LK and Thompson, MA (2012) The effect of spiral arms on star formation in the Galaxy. Monthly Notices of the Royal Astronomical Society, 426 (1). pp. 701-707. ISSN 0035-8711

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Open Access URL: https://arxiv.org/pdf/1204.1578.pdf (Accepted version)


We have examined the ratio between the integrated luminosity of massive young stellar objects detected by the Red MSX Source (RMS) survey and the mass of molecular clouds in the Galactic Ring Survey (GRS) region, as a function of Galactocentric radius. The results indicate that 60-80per cent of the observed increases in the star formation rate density associated with spiral-arm features are due to source crowding within the arms. Of the remainder, most of the increase in the inner Sagittarius arm is due to an enhancement in the simple star formation efficiency, i.e. in the number of RMS sources per unit molecular gas mass. In the inner Perseus arm, the residual increase is due to a higher than average mean source luminosity, which implies a top-heavy initial mass function, and this is entirely due to the presence, in the GRS region, of the W49 star-forming complex, which appears to be exceptional in its nature. The results also suggest that there is little or no increase in the star formation efficiency on kiloparsec scales in the Scutum tangent region which includes W43. We discuss the possible role played by the spiral arms in influencing the star formation efficiency and conclude that the most likely mechanisms are related to orbit crowding within the arms. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
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Date Deposited: 09 Mar 2018 09:47
Last Modified: 04 Sep 2021 10:41
DOI or ID number: 10.1111/j.1365-2966.2012.21740.x
URI: https://researchonline.ljmu.ac.uk/id/eprint/8237
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