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

doi:10.1086/186965

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

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

41 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 language	English (US)
Pages (from-to)	L85-L88
Journal	Astrophysical Journal
Volume	413
Issue number	2 PART 2
DOIs	https://doi.org/10.1086/186965
State	Published - 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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10.1086/186965

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title = "OSSE observations of galactic 511 keV positron annihilation radiation: Initial phase 1 results",

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.",

keywords = "Galaxy: center, Gamma rays: observations, ISM: general, Nuclear reactions, nucleosynthesis, abundances",

author = "Purcell, {W. R.} and Grabelsky, {D. A.} and Ulmer, {M. P.} and Johnson, {W. N.} and Kinzer, {R. L.} and Kurfess, {J. D.} and Strickman, {M. S.} and Jung, {G. V.}",

year = "1993",

month = aug,

day = "20",

doi = "10.1086/186965",

language = "English (US)",

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AU - Purcell, W. R.

AU - Grabelsky, D. A.

AU - Ulmer, M. P.

AU - Johnson, W. N.

AU - Kinzer, R. L.

AU - Kurfess, J. D.

AU - Strickman, M. S.

AU - Jung, G. V.

PY - 1993/8/20

Y1 - 1993/8/20

N2 - 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.

AB - 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.

KW - Galaxy: center

KW - Gamma rays: observations

KW - ISM: general

KW - Nuclear reactions, nucleosynthesis, abundances

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SN - 0004-637X

VL - 413

SP - L85-L88

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART 2

ER -

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

Abstract

Keywords

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