Abstract
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.
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Bussard, R.W. et al.: The annihilation of galactic positrons. ApJ 228, 928 (1979)
Churazov, E. et al.: Positron annihilation spectrum from the Galactic Centre region observed by SPI/INTEGRAL. MNRAS 357, 1377 (2005)
Crannell, C.J. et al.: Formation of the 0.511 MeV line in solar flares. ApJ 210, 582 (1976)
Iwata, K., Greaves, R.G., Surko, C.M.: γ-ray spectra from positron annihilation on atoms and molecules, PhRvA 55, 3586 (1997)
Jean, P. et al.: Spectral analysis of the Galactic e +−e − annihilation emission. A& A 445, 579 (2006)
Johnson, W.N. et al.: The spectrum of low-energy gamma radiation from the Galactic-Center region. ApJ 172, L1 (1972)
Knödlseder, J. et al.: The all-sky distribution of 511 keV electron-positron annihilation emission. A& A 441, 513 (2005)
Leventhal, M. et al.: Detection of 511 keV positron annihilation radiation from the galactic center direction. ApJ 225, L11 (1978)
McKee, C.F., Ostriker, J.P.: A theory of the interstellar medium – three components regulated by supernova explosions in an inhomogeneous substrate. ApJ 218, 148 (1977)
Teegarden, B.J. et al.: INTEGRAL SPI limits on electron – positron annihilation radiation from the Galactic plane. ApJ 621, 296 (2005)
Vedrenne, G. et al.: SPI: The spectrometer aboard INTEGRAL. A& A 411, L63 (2003)
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Sazonov, S., Churazov, E., Sunyaev, R. et al. Annihilation of positrons in the Galaxy. Exp Astron 20, 15–22 (2005). https://doi.org/10.1007/s10686-006-9039-0
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DOI: https://doi.org/10.1007/s10686-006-9039-0