Testing the Larson relations in massive clumps

Monthly Notices of the Royal Astronomical Society2018Vol. 477(2), pp. 2220–2242

Citations Over TimeTop 10% of 2018 papers

A. Traficante, A. Duarte-Cabral, D. Elia, G. A. Fuller, Manuel Merello, S. Molinari, N. Peretto, E. Schisano, A. Di Giorgio

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.

Citations Over TimeTop 10% of 2018 papers

Abstract

Related Papers