An observation of the Galactic center region with the HEXAGONE high resolution gamma-ray spectrometer. [Sgr A; 1742-289]

Conference · Thu Aug 01 04:00:00 EDT 1991 · AIP Conference Proceedings (American Institute of Physics); (United States)

OSTI ID:7302460

Matteson, J; Pelling, M; Bowman, B; Briggs, M; Gruber, D; Lingenfelter, R; Peterson, L ^[1]; Lin, R; Smith, D; Feffer, P; Hurley, K ^[2]; Cork, C; Landis, D; Luke, P; Madden, N; Malone, D; Pehl, R; Pollard, M ^[3]; von Ballmoos, P; Niel, M ; Slassi, S; Vedrenne, G ^[4]; Durouchoux, P; Chapuis, C ^[5]

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1. Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, California 92093-0111 (United States)
2. Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
3. Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
4. Centre d'Etudes Spatiale Des Rayonnements, 31029 Toulouse Cedex (France)
5. Service d'Astrophysique, Departement de Physique Generale, Centre d'Etudes Nucleaires de Saclay, 91191 Gif-sur-Yvette Cedex (France)

The galactic center region was observed for 6 hours on 22 May 1989 from a high altitude balloon with the HEXAGONE high resolution gamma-ray spectrometer. The instrument had a 285 cm{sup 2} array of cooled germanium detectors with an energy resolution of 2.2 keV at 511 keV and an 18{degree} FWHM field of view. 511 keV gamma-rays from electron-positron annihilation and 1809 keV gamma-rays from the radioactive decay of {sup 26}Al were observed to have fluxes of 8.9{times}10{sup {minus}4} and 1.9{times}10{sup {minus}4} ph/cm{sup 2}-s, respectively. Continuum emission was detected from 20 to 800 keV and preliminary results have been obtained for the spectrum. Below 120 keV this is well described by power law with a slope of {minus}2.6. In the 120--250 keV band the spectrum contains a broad line-like feature with a flux of (2 to 6){times}10{sup {minus}3} ph/cm{sup 2}-s, depending on the assumed underlying continuum. This is interpreted as the result of Compton backscattering of {similar to}511 keV photons from a compact source of electron-positron annihilation radiation.

• OSTI ID: 7302460
• Report Number(s): CONF-901275--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Journal Volume: 232:1
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALUMINIUM 26
ALUMINIUM ISOTOPES
ANNIHILATION
ASTRONOMY
BASIC INTERACTIONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
COLLISIONS
DATA
DECAY
ELECTROMAGNETIC INTERACTIONS
ELECTRON COLLISIONS
ELECTRON-POSITRON COLLISIONS
ENERGY RANGE
EXPERIMENTAL DATA
GALAXIES
GALAXY NUCLEI
GAMMA ASTRONOMY
GAMMA SPECTRA
INFORMATION
INTERACTIONS
ISOTOPES
KEV RANGE
LIGHT NUCLEI
MEV RANGE
MEV RANGE 01-10
MILKY WAY
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
PARTICLE INTERACTIONS
POSITRON COLLISIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SPECTRA
YEARS LIVING RADIOISOTOPES