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ATLASGAL - properties of compact H II regions and their natal clumps

Urquhart, JS, Thompson, MA, Moore, TJT, Purcell, CR, Hoare, MG, Schuller, F, Wyrowski, F, Csengeri, T, Menten, KM, Lumsden, SL, Kurtz, S, Walmsley, CM, Bronfman, L, Morgan, LK, Eden, DJ and Russeil, D (2013) ATLASGAL - properties of compact H II regions and their natal clumps. Monthly Notices of the Royal Astronomical Society, 435 (1). pp. 400-428. ISSN 0035-8711

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Abstract

We present a complete sample of molecular clumps containing compact and ultracompact HII (UC HII) regions between ℓ = 10° and 60° and |b| < 1°, identified by combining the APEX Telescope Large Area Survey ofthe Galaxy submm and CORNISH radio continuum surveys with visual examination ofarchival infrared data. Our sample is complete to optically thin, compact and UC HII regions driven by a zero-age main-sequence star of spectral type B0 or earlier embedded within a 1000M clump. In total we identify 213 compact and UC HII regions, associated with 170 clumps. Unambiguous kinematic distances are derived for these clumps and used to estimate their masses and physical sizes, as well as the Lyman continuum fluxes and sizes of their embedded HII regions. We find a clear lower envelope for the surface density of molecular clumps hosting massive star formation of 0.05 g cm, which is consistent with a similar sample of clumps associated with 6.7 GHz masers. The mass of the most massive embedded starsis closely correlated with the mass of their natal clump. Young B stars appearto be significantly more luminous in the ultraviolet than predicted by current stellar atmosphere models. The properties of clumps associated with compact and UC HII regions are very similar to those associated with 6.7 GHz methanol masers and we speculate that there is little evolution in the structure of the molecular clumps between these two phases. Finally, we identifya significant peak in the surface density of compact and UC HII-regions associated with the W49A star-forming complex, noting that this complex is truly one of the most massive and intense regions of star formation in the Galaxy. © 2013 The Authors, Published by Oxford University Press on behalf of the Royal Astronomical Society.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2013 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
Related URLs:
Date Deposited: 08 Mar 2018 11:35
Last Modified: 08 Mar 2018 11:35
DOI or Identification number: 10.1093/mnras/stt1310
URI: http://researchonline.ljmu.ac.uk/id/eprint/8227

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