Abstract
The detection of the 0.511 MeV electron-positron annihilation line coming from the Galactic Center can provide the means to estimate the rate of positron production and to test some theoretical sources of positrons. In this work we present the result of the measurements of the 0.511 MeV line flux made in a gamma-ray experiment on board a stratospheric balloon. The detector field of view looked at the galactic longitude range -31 < ℓII < + 41°. The observed flux is (6.70 ± 0.85) x 10-3 photons cm-2 s-1, which is in good agreement with the expected flux when assuming that the Galactic Center is a line source emitting uniformly.
