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Energetic secondary electrons and the nonthermal galactic radio background - A probe of the magnetic field in interstellar cloudsA previous analysis of the manifestations of charged-pion-decay secondary electrons in interstellar cloud material is extended to include those contributions to the Galactic radio and soft gamma-ray backgrounds that are directly attributable to energetic secondaries. The equilibrium distribution of secondary electrons in dense interstellar clouds is calculated, synchrotron emissivity from isolated interstellar clouds is examined, and it is shown how the value of the magnetic field in these clouds may be determined by observing the radio emission in their directions. The contribution that such clouds make to the integrated radio background is evaluated, and the Galactic distribution of bremsstrahlung gamma rays that arise from interactions of secondary electrons with thermal material in dense clouds is computed. The results indicate that a magnetic field of no more than 80 microgauss is characteristic of dense clouds and that the integrated synchrotron radiation from secondary electrons in interstellar clouds will contribute a significant fraction of the nonthermal brightness along the Galactic equator even if the mean cloud field is as low as 35 microgauss.
Document ID
19780048565
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Marscher, A. P.
(NASA Goddard Space Flight Center Laboratory for High Energy Astrophysics, Greenbelt, Md.; Virginia, University, Charlottesville, Va.;, United States)
Brown, R. L.
(National Radio Astronomy Observatory Green Bank, W. Va., United States)
Date Acquired
August 9, 2013
Publication Date
April 15, 1978
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
78A32474
Distribution Limits
Public
Copyright
Other

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