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Title: G0.253+0.016: A centrally condensed, high-mass protocluster

Despite their importance as stellar nurseries and the building blocks of galaxies, very little is known about the formation of the highest mass clusters. The dense clump G0.253+0.016 represents an example of a clump that may form an Arches-like, high-mass cluster. Here we present molecular line maps toward G0.253+0.016 taken as part of the MALT90 molecular line survey, complemented with APEX observations. Combined, these data reveal the global physical properties and kinematics of G0.253+0.016. Recent Herschel data show that while the dust temperature is low (∼19 K) toward its center, the dust temperature on the exterior is higher (∼27 K) due to external heating. Our new molecular line data reveal that, overall, the morphology of dense gas detected toward G0.253+0.016 matches its IR extinction and dust continuum emission very well. An anticorrelation between the dust and gas column densities toward its center indicates that the clump is centrally condensed with a cold, dense interior in which the molecular gas is chemically depleted. The velocity field shows a strong gradient along the clump's major axis, with the blueshifted side at a higher Galactic longitude. The optically thick gas tracers are systematically redshifted with respect to the optically thin and hot gasmore » tracers, indicating radial motions. The gas kinematics and line ratios support the recently proposed scenario in which G0.253+0.016 results from a tidal compression during a recent pericenter passage near Sgr A*. Because G0.253+0.016 represents an excellent example of a clump that may form a high-mass cluster, its detailed study should reveal a wealth of knowledge about the early stages of cluster formation.« less
Authors:
; ;  [1] ; ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia)
  2. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany)
  3. Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)
  4. Universidad de Chile, Camino El Observatorio1515, Las Condes, Santiago (Chile)
  5. University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria)
  6. Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 8030 (United States)
  7. Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)
  8. Max-Planck Institut fur Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22356895
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPRESSION; DENSITY; DUSTS; EMISSION; GALAXIES; HEATING; MAPS; MASS; RED SHIFT; STARS