ISSN:
1572-9672
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The modern state of gamma-ray astronomy is reviewed, the paper being mainly devoted to the theoretical models that describe generation of gamma-ray emission under astrophysical conditions. Basic information on the processes of generation and absorption of gamma-rays, as well as the results of observations for various gamma-ray photon energies are reported. In the region of soft gamma-ray emission (i.e., for energies less than tens of MeV), where emission in gamma-ray lines dominates, we also discuss the nature of gamma-ray bursts, the origin of gamma-ray emission from the galactic centre, etc. Discrete sources and, in particular, the mysterious source Cyg X-3 are discussed in the region of very high (E γ 〉 1012 eV) and ultra-high (E γ 〉 1015 eV) energy gamma-ray emission. A larger portion of the review is devoted to the analysis of cosmic-ray origin on the basis of the available gamma-ray data in the region from several tens of MeV to several GeV. The peculiarity of this energy range is, in particular, in the fact that the diffuse galactic emission was observed mainly there. We also discuss the problem of determination of the cosmic-ray density gradient from the gamma-ray data. The origin of high-latitude gamma-ray emission, the problem of galactic gamma-ray halo, etc., are discussed. The theoretical models explaining the nature of unidentified gamma-ray sources, as well as the results of measurements and theoretical estimations of a gamma-ray flux from SN1987A are analysed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00241870
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