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Testing the Larson relations in massive clumps

Traficante, A., Duarte Cabral, Ana, Elia, D., Fuller, G. A., Merello, M., Molinari, S., Peretto, N., Schisano, E. and Di Giorgio, A. 2018. Testing the Larson relations in massive clumps. Monthly Notices of the Royal Astronomical Society 477 (2) , pp. 2220-2242. 10.1093/mnras/sty798

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Abstract

We tested the validity of the three Larson relations in a sample of 213 massive clumps selected from the Herschel infrared Galactic Plane (Hi-GAL) survey, also using data from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey of 3-mm emission lines. The clumps are divided into five evolutionary stages so that we can also discuss the Larson relations as a function of evolution. We show that this ensemble does not follow the three Larson relations, regardless of the clump's evolutionary phase. A consequence of this breakdown is that the dependence of the virial parameter αvir on mass (and radius) is only a function of the gravitational energy, independent of the kinetic energy of the system; thus, αvir is not a good descriptor of clump dynamics. Our results suggest that clumps with clear signatures of infall motions are statistically indistinguishable from clumps with no such signatures. The observed non-thermal motions are not necessarily ascribed to turbulence acting to sustain the gravity, but they might be a result of the gravitational collapse at the clump scales. This seems to be particularly true for the most massive (M ≥ 1000 M⊙) clumps in the sample, where exceptionally high magnetic fields might not be enough to stabilize the collapse.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: Oxford University Press
ISSN: 0035-8711
Date of First Compliant Deposit: 29 May 2018
Date of Acceptance: 22 March 2018
Last Modified: 07 Feb 2019 09:54
URI: http://orca.cf.ac.uk/id/eprint/111804

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