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The lesser role of shear in galactic star formation: Insight from the galactic ring survey

Dib, S., Helou, G., Moore, T.J.T., Urquhart, J.S., Dariush, A. (2012) The lesser role of shear in galactic star formation: Insight from the galactic ring survey. Astrophysical Journal, 758 (2). p. 125. ISSN 0004-637X. (doi:10.1088/0004-637X/758/2/125) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1088/0004-637X/758/2/125

Abstract

We analyze the role played by shear in regulating star formation in the Galaxy on the scale of individual molecular clouds. The clouds are selected from the 13CO J = 1-0 line of the Galactic Ring Survey. For each cloud, we estimate the shear parameter which describes the ability of density perturbations to grow within the cloud. We find that for almost all molecular clouds considered, there is no evidence that shear is playing a significant role in opposing the effects of self-gravity. We also find that the shear parameter of the clouds does not depend on their position in the Galaxy. Furthermore, we find no correlations between the shear parameter of the clouds with several indicators of their star formation activity. No significant correlation is found between the shear parameter and the star formation efficiency of the clouds which is measured using the ratio of the massive young stellar objects luminosities, measured in the Red MSX survey, to the cloud mass. There are also no significant correlations between the shear parameter and the fraction of their mass that is found in denser clumps which is a proxy for their clump formation efficiency, nor with their level of fragmentation expressed in the number of clumps per unit mass. Our results strongly suggest that shear is playing only a minor role in affecting the rates and efficiencies at which molecular clouds convert their gas into dense cores and thereafter into stars.

Item Type: Article
DOI/Identification number: 10.1088/0004-637X/758/2/125
Additional information: Unmapped bibliographic data: C7 - 125 [EPrints field already has value set] LA - English [Field not mapped to EPrints] J2 - Astrophys. J. [Field not mapped to EPrints] AD - Astrophysics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom [Field not mapped to EPrints] AD - Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, United States [Field not mapped to EPrints] AD - Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, United Kingdom [Field not mapped to EPrints] AD - Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: galaxies: ISM, ISM: clouds, ISM: molecules, stars: formation
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 30 Nov 2015 14:59 UTC
Last Modified: 29 May 2019 16:28 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/52207 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
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