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Positron Annihilations at the Galactic Center: Generating More Questions Than Answers

Hasan Yuksel
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Abstract

The bulge of our Galaxy is illuminated by the 0.511 MeV gamma-ray line flux from annihilations of nonrelativistic positrons. The emission is strongly concentrated at the Galactic Center, in contrast to gamma-ray maps tracing nucleosynthesis (e.g., the 1.809 MeV line from decaying ^26Al) or cosmic ray processes (e.g., the 1-30 MeV continuum), which reveal a bright disk with a much less prominent central region. If positrons are generated at relativistic energies, higher-energy gamma rays will also be produced from inflight annihilation of positrons on ambient electrons. The comparison of the gamma-ray spectrum from inflight annihilation to the observed diffuse Galactic gamma-ray data constrains the injection energies of Galactic positrons to be less than 3 MeV.

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Hasan Yuksel. 2006-09-06. Positron Annihilations at the Galactic Center: Generating More Questions Than Answers. https://doi.org/10.1016/j.nuclphysbps.2007.08.031

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