OSSE Observations of Galactic 511 keV Positron Annihilation Radiation: Initial Phase 1 Results
NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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The Oriented Scintillation Spectrometer Experiment OSSE on the Compton Gamma-Ray Observatory GRO has performed numerous observations of the galactic plane and galactic center region to measure the distribution of galactic 511 keV positron annihilation radiation and to search for time variability of the emission the initial 511 keV line fluxes for the observations performed during the first 18 months of the GRO mission are presented. The 511 keV line flux for a typical galactic center observation is 25 plus or minus 03 x 10exp -1 gamma sq cm sexp -1, where the quoted uncertainty represents the 1 sigma statistical uncertainty. No statistically significant time variability of the line flux has been observed the 3 sigma upper linit to daily variations from the mean is 3 x 10exp -4 gamma sq cm sexp -1. The distribution of galactic 511 keV positron annihilation radiation implied by the OSSE observations is discussed and compared with observations by other instruments.
- Nuclear Physics and Elementary Particle Physics