ALMA-IRDC: dense gas mass distribution from cloud to core scales
Artikel i vetenskaplig tidskrift, 2021
Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high mass star formation (HMSF). Here, we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as some of the best candidates to study HMSF within the Milky Way. To do so, we have obtained a set of large mosaics covering these IRDCs with Atacama Large Millimeter/submillimeter Array (ALMA) at Band 3 (or 3 mm). These observations have a high angular resolution (similar to 3 arcsec; similar to 0.05 pc), and high continuum and spectral line sensitivity (similar to 0.15 mJy beam(-1) and similar to 0.2 K per 0.1 km s(-1) channel at the N2H+ (1 - 0) transition). From the dust continuum emission, we identify 96 cores ranging from low to high mass (M = 3.4-50.9M(circle dot)) that are gravitationally bound (alpha(vir) = 0.3-1.3) and which would require magnetic field strengths of B = 0.3-1.0 mG to be in virial equilibrium. We combine these results with a homogenized catalogue of literature cores to recover the hierarchical structure within these clouds over four orders of magnitude in spatial scale (0.01-10 pc). Using supplementary observations at an even higher angular resolution, we find that the smallest fragments (<0.02 pc) within this hierarchy do not currently have the mass and/or the density required to form high-mass stars. None the less, the new ALMA observations presented in this paper have facilitated the identification of 19 (6 quiescent and 13 star-forming) cores that retain >16M(circle dot) without further fragmentation. These high-mass cores contain trans-sonic non-thermal motions, are kinematically sub-virial, and require moderate magnetic field strengths for support against collapse. The identification of these potential sites of HMSF represents a key step in allowing us to test the predictions from high-mass star and cluster formation theories.
stars: massive
ISM: clouds
stars: formation
Författare
A. T. Barnes
Universität Bonn
J. D. Henshaw
Max-Planck-Gesellschaft
F. Fontani
Max-Planck-Institut für extraterrestrische Physik
Istituto nazionale di astrofisica (INAF)
J. E. Pineda
Max-Planck-Institut für extraterrestrische Physik
Giuliana Cosentino
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Jonathan Tan
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
University of Virginia
P. Caselli
Max-Planck-Institut für extraterrestrische Physik
I Jimenez-Serra
Centro de Astrobiología (INTA-CSIC)
Chi Yan Law
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
A. Avison
University of Manchester
F. Bigiel
Universität Bonn
S. Feng
Chinese Academy of Sciences
National Institutes of Natural Sciences
Academia Sinica
S. Kong
University of Arizona
S. N. Longmore
Liverpool John Moores University
L. Moser
Universität Bonn
R. J. Parker
University of Sheffield
A. Sanchez-Monge
Universität zu Köln
K. Wang
Beijing University of Technology
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 503 3 4601-4626Ämneskategorier
Subatomär fysik
Astronomi, astrofysik och kosmologi
Annan fysik
DOI
10.1093/mnras/stab803