OSSE observations of positron annihilation in the galactic plane
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
OSSE has measured the galactic longitude distribution of both the 511 keV annihilation line radiation and the three-photon positronium continuum within 40 degrees of the center. They have similar shapes, with a composite longitude distribution well represented by an 11 degrees FWHM Gaussian central bulge together with a possible broad disk component comprising as much as 15 of the integral flux between 40 degrees and 320 degrees longitude. Contributions from one or more discrete sources at or near the center with total annihilation radiation line plus continuum intensities of up to 4 x 10exp -4 photons cu cm secexp -1 2 sigma upper limit are compatible with the observed distribution. The best estimate of the positronium fraction is 0.97 plus or minus 0.03. No evidence for variation in the positronium fraction is observed.
- Nuclear Physics and Elementary Particle Physics