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The distribution of cosmic rays in the galaxy and their dynamics as deduced from recent gamma ray observationsData from SAS-2 on the galactic gamma ray line flux as a function of longitude is examined. It is shown that the gamma ray emissivity varies with galactocentric distance and is about an order of magnitude higher than the local value in a toroidal region between 4 and 5 kpc from the galactic center. This enhancement is accounted for in part by first-order Fermi acceleration, compression, and trapping of cosmic rays consistent with present ideas of galactic dynamics and galactic structure theory. Calculations indicate that cosmic rays in the 4 to 5 kpc region are trapped and accelerated over a mean time of the order of a few million years or about 2 to 4 times the assumed trapping time in the solar region of the galaxy on the assumption that only an increased cosmic ray flux is responsible for the observed emission. Cosmic ray nucleons, cosmic ray electrons, and ionized hydrogen gas were found to have a strikingly similar distribution in the galaxy according to both the observational data and the theoretical model discussed.
Document ID
Document Type
Conference Paper
Puget, J. L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Stecker, F. W. (Meudon Obs.)
Date Acquired
August 8, 2013
Publication Date
November 1, 1974
Publication Information
Publication: ESRO The Context and Status of Gamma Ray Astronomy
Subject Category
Distribution Limits
Work of the US Gov. Public Use Permitted.