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SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk

Urquhart, J.S., Figura, C., Cross, J.R., Wells, M.R.A., Moore, T.J.T., Eden, D.J., Ragan, S.E., Pettitt, A.R., Duarte-Cabral, A., Colombo, D., and others. (2020) SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk. Monthly Notices of the Royal Astronomical Society, 500 (3). pp. 3050-3063. ISSN 0035-8711. (doi:10.1093/mnras/staa2512) (KAR id:82505)


By combining two surveys covering a large fraction of the molecular material in the Galactic disk we investigate the role the spiral arms play in the star formation process. We have matched clumps identified by ATLASGAL with their parental GMCs as identified by SEDIGISM, and use these giant molecular cloud (GMC) masses, the bolometric luminosities, and integrated clump masses obtained in a concurrent paper to estimate the dense gas fractions (\(DGF_{gmc} = ∑M_{clump}/M_{gmc}\)) and the instantaneous star forming efficiencies (i.e., \(SFE_{gmc} = ∑L_{clump}/M_{gmc}\)). We find that the molecular material associated with ATLASGAL clumps is concentrated in the spiral arms (∼60 per cent found within ±10 km s\(^{−1}\) of an arm). We have searched for variations in the values of these physical parameters with respect to their proximity to the spiral arms, but find no evidence for any enhancement that might be attributable to the spiral arms. The combined results from a number of similar studies based on different surveys indicate that, while spiral-arm location plays a role in cloud formation and HI to H\(_2\) conversion, the subsequent star formation processes appear to depend more on local environment effects. This leads us to conclude that the enhanced star formation activity seen towards the spiral arms is the result of source crowding rather than the consequence of a any physical process.

Item Type: Article
DOI/Identification number: 10.1093/mnras/staa2512
Subjects: Q Science > QB Astronomy
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: James Urquhart
Date Deposited: 18 Aug 2020 14:56 UTC
Last Modified: 09 Dec 2022 01:13 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

Urquhart, J.S..

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Cross, J.R..

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Wells, M.R.A..

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Billington, S.J..

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