Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular clouds
Journal article, 2019

Young massive clusters (YMCs) are the most compact, high-mass stellar systems still forming at the present day. The precursor clouds to such systems are, however, rare due to their large initial gas mass reservoirs and rapid dispersal time-scales due to stellar feedback. None the less, unlike their high-z counterparts, these precursors are resolvable down to the sites of individually forming stars, and hence represent the ideal environments in which to test the current theories of star and cluster formation. Using high angular resolution (1 arcsec / 0.05 pc) and sensitivity ALMA observations of two YMC progenitor clouds in the Galactic Centre, we have identified a suite of molecular line transitions - e.g. c-C3H2 (7 - 6) - that are believed to be optically thin, and reliably trace the gas structure in the highest density gas on star-forming core scales. We conduct a virial analysis of the identified core and proto-cluster regions, and show that half of the cores (5/10) and both proto-clusters are unstable to gravitational collapse. This is the first kinematic evidence of global gravitational collapse in YMC precursor clouds at such an early evolutionary stage. The implications are that if these clouds are to form YMCs, then they likely do so via the 'conveyor-belt' mode, whereby stars continually form within dispersed dense gas cores as the cloud undergoes global gravitational collapse. The concurrent contraction of both the cluster-scale gas and embedded (proto-)stars ultimately leads to the high (proto-)stellar density in YMCs.

ISM: clouds

Galaxy: centre

stars: formation

Author

Ashley T. Barnes

University of Bonn

Liverpool John Moores University

Max Planck Society

S. Longmore

Liverpool John Moores University

A Avison

University of Manchester

UK Atacama Large Millimeter/submillimeter Array Regional Centre Node

Y. Contreras

Leiden University

A. Ginsburg

National Radio Astronomy Observatory Socorro

Jonathan D. Henshaw

Max Planck Society

J. M. Rathborne

Commonwealth Scientific and Industrial Research Organisation (CSIRO)

D. L. Walker

Atacama Large Millimeter-submillimeter Array (ALMA)

National Astronomical Observatory of Japan

J. Alves

University of Vienna

J. Bally

University of Colorado at Boulder

C. Battersby

University of Connecticut

M. T. Beltrán

Arcetri Astrophysical Observatory

H. Beuther

Max Planck Society

G. Garay

University of Chile (UCH)

L. Gomez

Atacama Large Millimeter-submillimeter Array (ALMA)

J. M. Jackson

NASA Ames Research Center

Jouni Kainulainen

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

J. M. D. Kruijssen

Astronomisches Rechen-Institut Heidelberg

X. Lu

National Astronomical Observatory of Japan

E. A. C. Mills

Brandeis University

J. Ott

National Radio Astronomy Observatory Socorro

T. Peters

Max Planck Society

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 486 1 283-303

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Other Physics Topics

DOI

10.1093/mnras/stz796

More information

Latest update

12/18/2019