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Detection of interstellar CH in the far-infraredThe first astronomical detection of CH in the far-infrared has been made. A ground state of rotational transition was observed in absorption against the far-infrared continuum peak of Sgr B2. The lines are resolved at a velocity resolution of 62 km/s, have a line width of roughly 250 km/s, and a line center optical depth of about 0.29. The inferred total column density of CH in the ground state along the line of sight is roughly 1.6 x 10 to the 15th/sq cm. Comparison of the far-infrared profiles to the 3 GHz emission lines confirms that the ground-state Lambda-doublet levels are inverted and gives an accurate estimate of the excitation temperature. The excitation temperature of the 3264 MHz line varies from cloud to cloud along the line of sight, the levels being most inverted in the Sgr B2 molecular cloud. The large intensity of the 3264 MHz line in this cloud relative to other clouds along the line of sight may thus be primarily an excitation effect.
Document ID
19870046563
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Stacey, Gordon J.
(California Univ. Berkeley, CA, United States)
Lugten, J. B.
(California Univ. Berkeley, CA, United States)
Genzel, R.
(California, University Berkeley, United States)
Date Acquired
August 13, 2013
Publication Date
February 15, 1987
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 313
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
87A33837
Funding Number(s)
CONTRACT_GRANT: NAG2-208
Distribution Limits
Public
Copyright
Other

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