OSSE observations of galactic 511 keV positron annihilation radiation: Initial phase 1 results

W. R. Purcell*, D. A. Grabelsky, M. P. Ulmer, W. N. Johnson, R. L. Kinzer, J. D. Kurfess, M. S. Strickman, G. V. Jung

*Corresponding author for this work

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

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 (2.5 ± 0.3) × 10-4 γ cm-2 s-1, where the quoted uncertainty represents the 1 σ statistical uncertainty. No statistically significant time variability of the line flux has been observed; the 3 σ upper limit to daily variations from the mean is 3 × 10-4 γ cm-2 s-1. The distribution of Galactic 511 keV positron annihilation radiation implied by the OSSE observations is discussed and compared with observations by other instruments.

Original languageEnglish (US)
Pages (from-to)L85-L88
JournalAstrophysical Journal
Volume413
Issue number2 PART 2
DOIs
StatePublished - Aug 20 1993

Keywords

  • Galaxy: center
  • Gamma rays: observations
  • ISM: general
  • Nuclear reactions, nucleosynthesis, abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Purcell, W. R., Grabelsky, D. A., Ulmer, M. P., Johnson, W. N., Kinzer, R. L., Kurfess, J. D., Strickman, M. S., & Jung, G. V. (1993). OSSE observations of galactic 511 keV positron annihilation radiation: Initial phase 1 results. Astrophysical Journal, 413(2 PART 2), L85-L88. https://doi.org/10.1086/186965