| タイトル | Compton-backscattered annihilation radiation from the Galactic Center region |
| 著者（英） | Feffer, P.; Lin, R. P.; Slassi, S.; Hurley, K.; Pelling, R. M.; Bowman, H. B.; Briggs, M.; Gruber, D.; Matteson, J.; Smith, D. M. |
| 著者所属（英） | NASA Headquarters |
| 発行日 | 1993-09-01 |
| 言語 | eng |
| 内容記述 | On 1989 May 22, the High Energy X-ray and Gamma-ray Observatory for Nuclear Emissions, a balloon-borne high-resolution germanium spectrometer with an 18-deg FOV, observed the Galactic Center (GC) from 25 to 2500 keV. The GC photon spectrum is obtained from the count spectrum by a model-independent method which accounts for the effects of passive material in the instrument and scattering in the atmosphere. Besides a positron annihilation line with a flux of (10.0 +/- 2.4) x 10 exp -4 photons/sq cm s and a full width at half-maximum (FWHM) of (2.9 + 1.0, -1.1) keV, the spectrum shows a peak centered at (163.7 +/- 3.4) keV with a flux of (1.55 +/- 0.47) x 10 exp -3 photons/sq cm s and a FWHM of (24.4 +/- 9.2) keV. The energy range 450-507 keV shows no positronium continuum associated with the annihilation line, with a 2-sigma upper limit of 0.90 on the positronium fraction. The 164 keV feature is interpreted as Compton backscatter of broadened and redshifted annihilation radiation, possibly from the source 1E 1740.7-2942. |
| NASA分類 | SPACE RADIATION |
| レポートNO | 93A55240 |
| 権利 | Copyright |
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