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Submillimeter and far infrared line observations of M17 SW: A clumpy molecular cloud penetrated by UV radiationMillimeter, submillimeter, and far infrared spectroscopic observations of the M17 SW star formation region are discussed. The results require the molecular cloud near the interface to be clumpy or filamentary. As a consequence, far ultraviolet radiation from the central OB stellar cluster can penetrate into the dense molecular cloud to a depth of several pc, thus creating bright and extended (CII) emission from the photodissociated surfaces of dense atomic and molecular clumps or sheets. The extended (CII) emission throughout the molecular cloud SW of the M17 complex has a level 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. This suggests that the molecular cloud as a whole is penetrated by ultraviolet radiation and has a clumpy or filamentary structure. The number of B stars expected to be embedded in the M17 molecular cloud probably can provide the UV radiation necessary for the extended (CII) emission. Alternatively, the UV radiation could be external, if the interstellar radiation in the vicinity of M17 is higher than in the solar neighborhood.
Document ID
19880014317
Document Type
Preprint (Draft being sent to journal)
Authors
Stutzki, J. (Max-Planck-Inst. fuer Extraterrestrische Physik Garching (Germany, F.R.), United States)
Stacey, G. J. (California Univ. Berkeley., United States)
Genzel, R. (Max-Planck-Inst. fuer Extraterrestrische Physik Garching (Germany, F.R.), United States)
Harris, A. I. (California Univ. Berkeley., United States)
Jaffe, d. T. (Texas Univ. Austin., United States)
Lugten, J. B. (California Univ. Berkeley., United States)
Date Acquired
August 13, 2013
Publication Date
November 1, 1987
Subject Category
ASTRONOMY
Report/Patent Number
NASA-CR-182866
NAS 1.26:182866
MPE-PREPRINT-103
Funding Number(s)
CONTRACT_GRANT: NSF AST-83-51381
CONTRACT_GRANT: NAG2-208
Distribution Limits
Public
Copyright
Other