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The galactic distribution (in radius and Z) of interstellar molecular hydrogen

Scoville, N. Z. and Solomon, P. M. and Sanders, D. B. (1977) The galactic distribution (in radius and Z) of interstellar molecular hydrogen. In: The Structure and Content of the Galaxy and Galactic Gamma Rays. NASA , Washington, DC, pp. 151-161.

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Observations of the galactic longitude and latitude distributions of lambda = 2.6 mm CO emission are presented. Analysis of these spectral-line data yields the large-scale distribution of molecular clouds in the galactic disk and their z-distribution out of the disk. Strong maxima in the number of molecular clouds occur in the galactic nucleus and at galactic radii 4 to 8 kpc. The peak at 4 to 8 kpc correlates well with a region of enhanced 100-MeV γ-ray emissivity. This correlation strongly supports the conclusion that the γ-rays are produced as a result of cosmic ray interactions in molecular H_2 clouds rather than in H(I). The width of the cloud layer perpendicular to the galactic plane between half-density points is 105 ± 15 pc near the 5.5-kpc peak. The total mass of molecular gas in the interior of the galaxy exceeds that of atomic hydrogen and is 3·10^9 M⊙ based on these observations.

Item Type:Book Section
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URLURL TypeDescription
Scoville, N. Z.0000-0002-0438-3323
Sanders, D. B.0000-0002-1233-9998
Additional Information:© 1977 Provided by the NASA Astrophysics Data System. This paper is Contribution 232 of the Five College Observatories. The research of Nicholas Scoville is partially supported by NSF Grant MPS73-D4949.
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NSFMPS 73-D4949
Record Number:CaltechAUTHORS:20190417-113053616
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94748
Deposited By: Tony Diaz
Deposited On:17 Apr 2019 21:38
Last Modified:03 Oct 2019 21:06

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