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Temperature and density distribution in the molecular gas toward westerlund 2: Further evidence for physical association


Ohama, A and Dawson, JR and Furukawa, N and Kawamura, A and Moribe, N and Yamamoto, H and Okuda, T and Mizuno, N and Onishi, T and Maezawa, H and Minamidani, T and Mizuno, A and Fukui, Y, Temperature and density distribution in the molecular gas toward westerlund 2: Further evidence for physical association, The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics, 709, (2) pp. 975-982. ISSN 0004-637X (2010) [Refereed Article]

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Copyright 2010 The American Astronomical Society.

DOI: doi:10.1088/0004-637X/709/2/975


Furukawa et al. reported the existence of a large mass of molecular gas associated with the super star cluster Westerlund 2 and the surrounding H II region RCW49, based on a strong morphological correspondence between NANTEN2 12CO(J = 2-1) emission and Spitzer IRAC images of the H II region. We here present temperature and density distributions in the associated molecular gas at ~3.5 pc resolution, as derived from a large velocity gradient analysis of the 12CO(J = 2-1), 12CO(J = 1-0), and 13CO(J = 2-1) transitions. The kinetic temperature is as high as ~60-150 K within a projected distance of ~5-10 pc from Westerlund 2 and decreases to as low as ~10 K away from the cluster. The high temperature provides robust verification that the molecular gas is indeed physically associated with the H II region, supporting Furukawa et al.'s conclusion. The derived temperature is also roughly consistent with theoretical calculations of photodissociation regions (PDRs), while the low spatial resolution of the present study does not warrant a more detailed comparison with PDR models. We suggest that the molecular clouds presented here will serve as an ideal laboratory to test theories on PDRs in future higher resolution studies.

Item Details

Item Type:Refereed Article
Keywords:ISM: clouds; ISM: individual objects (RCW49); open clusters and associations: individual (Westerlund 2)
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Dawson, JR (Dr Joanne Dawson)
ID Code:74988
Year Published:2010
Web of Science® Times Cited:89
Deposited By:Mathematics and Physics
Deposited On:2011-12-22
Last Modified:2015-02-23

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