Variable position annihilation radiation from the galactic center region

Journal Article · Sat Aug 15 04:00:00 EDT 1981 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/183613· OSTI ID:5874457

Riegler, G R; Ling, J C; Mahoney, W A; Wheaton, W A; Willett, J B; Jacobson, A S; Prince, T A

The HEAO 3 Cosmic Gamma-Ray Spectrometer performed the first high spectral resolution survey of the entire sky at gamma-ray energies from 50 keV to 10 MeV. Studies of 511 keV positron annihilation radiation from the vicinity of the galactic center are reported here, based on data which were recorded during 1979 September/October and 1980 March/April. The 1979 fall data show unshifted, narrow 511 keV line emission of intensity (1.85 +- 0.21) x 10/sup -3/ photons cm/sup -2/ s/sup -1/, consistent with earlier measurments. The 1980 spring measurement showed a statistically significant reduction in 511 keV emission from this region, thus requiring that a significant fraction of the flux originate in one or more compact sources of size < or =10/sup 18/ cm. While distribution of sources within approx.22/sup 0/ (at 90% confidence level) of the direction of the galactic center are allowed by the observations, the data rule out most extended models for positron production, such as by cosmic ray interaction in the interstellar medium or by distributions of many supernovae, novae, or pulsars. The data are well satisfied by assuming that the emission originates in a single compact source at the galactic center.

• Research Organization: Jet Propulsion Laboratory, California Institute of Technology
• OSTI ID: 5874457
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 248:1; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics &amp; Cosmology-- Cosmic Radiation
640105 -- Astrophysics &amp; Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
COSMIC PHOTONS
COSMIC RADIATION
DATA ANALYSIS
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION SPECTRA
FERMIONS
GALAXIES
GALAXY NUCLEI
GAMMA RADIATION
GAMMA SPECTRA
INTERACTIONS
IONIZING RADIATIONS
LEPTONS
MASSLESS PARTICLES
MEASURING INSTRUMENTS
MILKY WAY
PHOTONS
POSITRONS
RADIATION FLUX
RADIATIONS
SPECTRA
SPECTROMETERS
VARIATIONS