Testing the Larson relations in massive clumps

Traficante, A., Duarte Cabral, Ana ORCID: https://orcid.org/0000-0002-5259-4774, Elia, D., Fuller, G. A., Merello, M., Molinari, S., Peretto, N. ORCID: https://orcid.org/0000-0002-6893-602X, 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:	05 May 2023 10:55
URI:	https://orca.cardiff.ac.uk/id/eprint/111804

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