Cosmic-ray production and x-ray and gamma-ray emission from the galactic center

V. A. Dogiel, K. S. Cheng, D. O. Chernyshoy, V. Tatisoheff, C. M. Ko, W. H. Ip, M. Kokubun, Y. Maeda, K. Mitsuda

Research output: Contribution to journalArticlepeer-review


We assume that the energy source in the Galactic Center is the black hole Sgr A, which becomes active when a star is captured in a rate of ∼ 10-5yr-1. During the active phase relativistic protons with a characteristic energy ∼ 6 x 1052erg per capture are ejected. We suppose that the annihilation of secondary positrons produced by proton-proton collisions is observed as the 511 keV line flux from the Galactic bulge. Though these positron are generated with relatively high energies (> 30 MeV), our model satisfy the criterion derived by Beacom and Yiiksel based on the COMPTEL data in the range 1-30 MeV. From our estimations it follows also that a flux of gamma-ray de-excitation lines ∼ 2.5 x 10-5 ph cm-2 s-1 in the range below 8 MeV is produced by the relativistic protons in the Galactic center. A specific line is the one at 1.809 MeV from radioactivity of 26 Al. The predicted quasi-stationary flux of the 26Al 1.809 MeV line from the 1° x 1 central region is < 10-6 ph cm-2 s-1. We conclude also the the thermal 6.5 keV X-ray flux and the non-thermal hard X-ray flux in the range 14-40 keV observed by SUZAKU is emitted by subrelativistic protons produced by accretion processes.

Original languageEnglish
Pages (from-to)133-137
Number of pages5
JournalJournal of the Physical Society of Japan
Issue numberSUPPL. A
StatePublished - 2009


  • Galactic center
  • Gamma-rays
  • X-rays


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