G0.253 + 0.016: A Molecular Cloud Progenitor of an Arches-like Cluster

Author(s)
Steven N. Longmore, Jill Rathborne, Nate Bastian, Joao Alves, Joana Ascenso, John Bally, Leonardo Testi, Andy Longmore, Cara Battersby, Eli Bressert, Cormac Purcell, Andrew Walsh, James Jackson, Jonathan Foster, Sergio Molinari, Stefan Meingast, António E A Amorim, J. Lima, R. Marques, A. Moitinho, J. Pinhao, J. Rebordao, F. D. Santos
Abstract

Young massive clusters (YMCs) with stellar masses of 10(4)-10(5) M-circle dot and core stellar densities of 10(4)-10(5) stars per cubic pc are thought to be the "missing link" between open clusters and extreme extragalactic super star clusters and globular clusters. As such, studying the initial conditions of YMCs offers an opportunity to test cluster formation models across the full clustermass range. G0.253 + 0.016 is an excellent candidate YMC progenitor. We make use of existing multi-wavelength data including recently available far-IR continuum (Herschel/Herschel Infrared Galactic Plane Survey) and mm spectral line (H2O Southern Galactic Plane Survey and Millimetre Astronomy Legacy Team 90 GHz Survey) data and present new, deep, multiple-filter, near-IR (Very Large Telescope/NACO) observations to study G0.253 + 0.016. These data show that G0.253 + 0.016 is a high-mass (1.3 x 10(5) M-circle dot), low-temperature (T-dust similar to 20 K), high-volume, and column density (n similar to 8 x 10(4) cm(-3); N-H2 similar to 4 x 10(23) cm(-2)) molecular clump which is close to virial equilibrium (M-dust similar to M-virial) so is likely to be gravitationally bound. It is almost devoid of star formation and, thus, has exactly the properties expected for the initial conditions of a clump that may form an Arches-like massive cluster. We compare the properties of G0.253 + 0.016 to typical Galactic cluster-forming molecular clumps and find it is extreme, and possibly unique in the Galaxy. This uniqueness makes detailed studies of G0.253 + 0.016 extremely important for testing massive cluster formation models.

Organisation(s)
Department of Astrophysics
External organisation(s)
The University of Sydney, Harvard-Smithsonian Center for Astrophysics, James Cook University, Universidade de Lisboa, Universidade de Coimbra, Boston University, Excellence Cluster Universe, University of Exeter, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Universidade Técnica de Lisboa, European Southern Observatory (Germany), University of Colorado, Boulder, The Royal Observatory, Edinburgh, University of Leeds, INAF-Istituto Fisica Spazio Interplanetario
Journal
The Astrophysical Journal: an international review of astronomy and astronomical physics
Volume
746
ISSN
0004-637X
DOI
https://doi.org/10.1088/0004-637X/746/2/117
Publication date
02-2012
Peer reviewed
Yes
Austrian Fields of Science 2012
103004 Astrophysics
Portal url
https://ucrisportal.univie.ac.at/en/publications/9389f8f4-9b11-4bcb-a721-dbaa8cda8f5e