The Coronas-F Space Mission pp 175-256

Part of the Astrophysics and Space Science Library book series (ASSL, volume 400)

The Study of the Cosmic Gamma-Emission Nonstationary Fluxes Characteristics by the AVS-F Apparatus Data

  • Yu. D. Kotov
  • I. V. Arkhangelskaja
  • A. I. Arkhangelsky
  • S. N. Kuznetsov
  • A. S. Glyanenko
  • P. A. Kalmykov
  • D. B. Amandzholova
  • V. T. Samoylenko
  • V. N. Yurov
  • A. V. Pavlov
  • O. I. Chervyakova
  • I. V. Afonina
Chapter

Abstract

The AVS-F apparatus (Russian abbreviation for Amplitude-Time Spectrometry of the Sun) is intended for the solar flares’ hard X-ray and gamma-ray emission characteristic studies and for the search and detection of the gamma-ray bursts (GRB). At present over 1,100 events with duration more than 2 s without any coordinate relations to Earth Radiation Belts and South Atlantic Anomaly were separated on the results of preliminary analysis of AVS-F experiment database.About 68 % of the identified events were associated with quasistationary equatorial precipitations-15-30 % count rate increases in the low-energy gamma-band of the AVS-F apparatus over its average value obtained by approximation of these parts with polynomials discovered on some equatorial segments in the ranges of geographic latitude of 25 up to +30. Several short events with duration of 1-16 ms associated with terrestrial gamma-ray flashes were registered during the experiment. These events were detected above the powerful thunderstorm formations.Solar flares with classes stronger than M1.0 according to the GOES classification were about 7 % of the detected events. Solar flares’ hard X-rays and γ-emission were mainly observed during the rise or maximum phases of the emission in the soft X-rays band according to the detectors on board the GOES series satellites data and duration of their registration is less than of the soft X-ray bands. According to the preliminary data analysis gamma-emission with energy over 10 MeV was registered during 12 % of the observed flares. The emission in the energy band E ¿ 100 keV was registered during over 60 faint solar flares (of B and C classes according to the GOES and from several ones γ-quanta with energy up to several tens of MeV were observed.Several spectral line complexes were observed in the spectra of some solar flares stronger than M1.0 in the low-energy gamma-range. Registered spectral features were corresponded to α α-lines, annihilation line, nuclear lines, and neutron capture line on1H (2.223 MeV). In the spectrum of the January 20, 2005 solar flare the feature in the range of 15-21 MeV was detected for the first time. It can be associated with lines of 15.11 MeV (12C +16O) or 20.58 MeV (from neutron radiative capture on3He), or with their combination. Also several e-dominant flares without any gamma-lines in energy spectra were identified. All detected faint solar flares were e-dominant according to the preliminary data analysis.Thin structure with characteristic timescale of 30-160 s was observed at 99 % significance level on some solar flares stronger than M1.0 temporal profiles in the low-energy gamma-band in the energy ranges corresponding to the identified spectral features or whole gamma-band energy boundaries. According to the results of the preliminary analysis during the flare of January 20, 2005, thin structure with timescale from 7 ms to 35 ms was detected at 99 % confidence level in the energy range of 0.1-20 MeV. Some thin structure with characteristic timescale 50-110 s was observed on temporal profiles of several faint events.About 3 % of the identified events were gamma-ray bursts. During some bursts high-energy gamma-emission was observed, for example Emax = 147 ± 3 MeV for GRB050525.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Yu. D. Kotov
    • 1
  • I. V. Arkhangelskaja
    • 1
  • A. I. Arkhangelsky
    • 1
  • S. N. Kuznetsov
    • 2
  • A. S. Glyanenko
    • 1
  • P. A. Kalmykov
    • 1
  • D. B. Amandzholova
    • 1
  • V. T. Samoylenko
    • 1
  • V. N. Yurov
    • 1
  • A. V. Pavlov
    • 1
  • O. I. Chervyakova
    • 1
  • I. V. Afonina
    • 1
  1. 1.National Research Nuclear University “MEPhI”MoscowRussia
  2. 2.D. V. Skobeltsyn Institute of Nuclear PhysicsM. V. Lomonosov Moscow State University (SINP MSU)MoscowRussia

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