Experimental Astronomy

, Volume 20, Issue 1–3, pp 15–22 | Cite as

Annihilation of positrons in the Galaxy

  • S. SazonovEmail author
  • E. Churazov
  • R. Sunyaev
  • M. Revnivtsev
Original Article


Observations of electron-positron annihilation radiation from the Galactic Center region with the SPI instrument aboard INTEGRAL are summarized. The measured width of the 511 keV line and inferred fraction of positrons annihilating through positronium formation are consistent with the annihilation taking place in the warm ISM phase, although combinations of several ISM phases are also allowed by the data. The spatial distribution of 511 keV emission suggests that positron sources are concentrated toward the Galactic bulge and avoid the Galactic disk.


Galaxy: Center Gamma rays: Observations ISM: General 


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Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • S. Sazonov
    • 1
    • 2
    Email author
  • E. Churazov
    • 1
  • R. Sunyaev
    • 1
  • M. Revnivtsev
    • 1
  1. 1.Max-Planck-Institut für AstrophysikGarchingGermany
  2. 2.Space Research InstituteMoscowRussia

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