Centaurus A (NGC 5128) at 2 keV-2.3 MeV : HEAO 1 observations and implications.
Abstract
The active-nucleus galaxy Centaurus A has been studied at 2 keV-2.3 MeV using data from the UCSD/MIT hard X-ray and low-energy gamma-ray instrument and the GSFC/CIT cosmic X-ray experiment on HEAO-1. It is found that an E exp -1.60 + or - 0.03 power law spectrum breaking to E exp -2.0 + or - 0.2 at 140 keV best describes the January and July 1978 data. The average intensity was 50% higher during the January observations. Upper limits to unresolved lines at 511 keV and 1.6 MeV were found to be 6.5 x 10 to the -4th photons/sq cm-s and 2.2 x 10 to the -4th photons/sq cm-s, respectively, at the 90% confidence level. The present data are consistent with the detailed calculations of the synchrotron self-Compton mechanism; they may also agree, marginally, with the predictions of emission from spherical accretion onto black holes.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1981
- DOI:
- 10.1086/158719
- Bibcode:
- 1981ApJ...244..429B
- Keywords:
-
- Cosmic X Rays;
- Energy Spectra;
- Galactic Nuclei;
- Heao 1;
- Radio Galaxies;
- X Ray Sources;
- Active Galaxies;
- Astronomical Models;
- Black Holes (Astronomy);
- Compton Effect;
- Gamma Ray Astronomy;
- X Ray Spectra;
- Astronomy