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Cold atomic hydrogen in the inner galaxyThe VLA is used to measure 21 cm absorption in directions with the absolute value of b less than 1 deg., the absolute value of 1 less than 25 deg. to probe the cool atomic gas in the inner galaxy. Abundant H I absorption is detected; typical lines are deep and narrow, sometimes blending in velocity with adjacent features. Unlike 21 cm emission not all allowed velocities are covered: large portions of the l-v diagram are optically thin. Although not similar to H I emission, the absorption shows a striking correspondence with CO emission in the inner galaxy: essentially every strong feature detected in one survey is seen in the other. The provisional conclusion is that in the inner galaxy most cool atomic gas is associated with molecular cloud complexes. There are few or no cold atomic clouds devoid of molecules in the inner galaxy, although these are common in the outer galaxy.
Document ID
19870005652
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Dickey, J. M.
(Minnesota Univ. Minneapolis, MN, United States)
Garwood, R. W.
(Minnesota Univ. Minneapolis, MN, United States)
Date Acquired
August 13, 2013
Publication Date
October 1, 1986
Publication Information
Publication: NASA. Ames Research Center Summer School on Interstellar Processes: Abstracts of Contributed Papers
Subject Category
Astrophysics
Accession Number
87N15085
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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