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Submillimeter and far-infrared line observations of M17 SW - A clumpy molecular cloud penetrated by ultraviolet radiationMillimeter, submillimeter, and far-IR spectroscopic observations of the M17 SW star formation region are reported. Strong forbidden C II 158 micron and CO J = 7 - 6 line emission arises in an H II region/molecular cloud interface of several pc thickness. Weaker forbidden C II emission appears to be extended over 15 pc throughout the molecular cloud. CO J = 14 - 13 and forbidden O I 145 micron spectra indicate high temperatures and densities for both molecular and atomic gas in the interface. The results require the molecular cloud near the interface to be clumpy or filamentary. The extended forbidden C II emission throughout the molecular cloud has a level around 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. The high gas temperature of molecular material in the UV-illuminated interface region suggests that CO self-shielding and heating of CO by photoelectrons are important.
Document ID
19880063996
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Stutzki, J. (Max-Planck-Inst. fuer Physik und Astrophysik Garching, Germany)
Genzel, R. (Max-Planck-Inst. fuer Physik und Astrophysik Garching, Germany)
Harris, A. I. (Max-Planck-Institut fuer Physik und Astrophysik, Garching, Federal Republic of Germany; California, University Berkeley, United States)
Stacey, G. J. (California, University Berkeley, United States)
Jaffe, D. T. (Texas, University Austin; California, University, Berkeley, United States)
Date Acquired
August 13, 2013
Publication Date
September 1, 1988
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 332
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NAG2-208
CONTRACT_GRANT: NSF AST-83-51381
Distribution Limits
Public
Copyright
Other