Journal Article

Molecular clumps in the W51 giant molecular cloud

H. Parsons, M. A. Thompson, J. S. Clark and A. Chrysostomou

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 424, issue 3, pages 1658-1671
Published in print August 2012 | ISSN: 0035-8711
Published online August 2012 | e-ISSN: 1365-2966 | DOI:
Molecular clumps in the W51 giant molecular cloud

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In this paper, we present a catalogue of dense molecular clumps located within the W51 giant molecular cloud (GMC). This work is based on Heterodyne Array Receiver Programme 13CO J = 3–2 observations of the W51 GMC and uses the automated CLUMPFIND algorithm to decompose the region into a total of 1575 clumps of which 1130 are associated with the W51 GMC. We clearly see the distinct structures of the W51 complex and the high-velocity stream previously reported. We find the clumps have characteristic diameters of 1.4 pc, excitation temperatures of 12 K, densities of 5.6 × 1021 cm−2, surface densities 0.02 g cm−2 and masses of 90 M. We find a total mass of dense clumps within the GMC of 1.5 × 105 M, with only 1 per cent of the clumps detected by number and 4 per cent by mass found to be supercritical. We find a clump-forming efficiency of 14 ± 1 per cent for the W51 GMC and a supercritical clump-forming efficiency of per cent. Looking at the clump mass distribution, we find it is described by a single power law with a slope of above ∼100 M. By comparing locations of supercritical clumps and young clusters, we see that any future star formation is likely to be located away from the currently active W51A region.

Keywords: molecular data; catalogues; stars: formation; ISM: clouds; submillimetre: ISM

Journal Article.  10685 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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