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A study of M31, M87, NGC 253, and M82 in high-energy gamma raysThe data from the Energetic Gamma Ray Experiment Telescope (EGRET) all-sky survey are examined for emission from the nearby galaxies M31, M87, NGC 253, and M82 in the high-energy (E greater than MeV) gamma-ray range. No significant emission is observed from any of these galaxies. The derived upper limits for all four galaxies are consistent with that expected from cosmic-ray interactions. For M87, the combination of the high-energy gamma-ray and radio data point to a lower limit of 7 microG for the magnetic field in the disk and 4 microG for the magnetic field in the halo, consistent with equipartition arguments. A study of NGC 253 and M82 show that EGRET observations do not sufficiently constrain the mean cosmic-ray energy density to provide more details on the cosmic-ray distribution in starburst galaxies.
Document ID
19950038763
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1086/174044
Authors
Sreekumar, P. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bertsch, D. L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Dingus, B. L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Esposito, J. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Fichtel, C. E. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hartman, R. C. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hunter, S. D. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kanbach, G. (Max-Planck Inst. fuer Extraterrestrische Physik Garching, Germany)
Kniffen, D. A. (Hampden-Sydney College Hampden-Sydney, VA, United States)
Lin, Y. C. (Stanford Univ. Stanford, CA, United States)
Date Acquired
August 16, 2013
Publication Date
May 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 426
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A70362
Funding Number(s)
CONTRACT_GRANT: NAG5-1742
CONTRACT_GRANT: NAS5-31210
CONTRACT_GRANT: NAG5-1605
CONTRACT_GRANT: BMFT-50-QV-9095
Distribution Limits
Public
Copyright
Other

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