Seyfert galaxies as X-ray sources.
Abstract
Previous source identifications implying that Seyfert galaxies commonly are powerful X-ray sources are investigated from a statistical viewpoint and shown not to be chance coincidences. Results are also presented for a specific search of Ariel 5 data for X-ray emission from a large sample of Seyfert galaxies, using the point summation technique. Two positive identifications are obtained together with upper limits for 65 other Seyferts. Correlations of the X-ray luminosity with properties in other wavebands are examined, and the physical association between the X-ray emission and other components of Seyfert nuclei is discussed. The X-ray luminosity function of Seyfert galaxies is derived, their contribution to the isotropic X-ray background radiation is estimated, and the radiation mechanism is considered. It is concluded that: (1) X-ray emission at power levels of 10 to the (42nd to 45th) power erg/s in the 2-10-keV band is a common property of type I Seyferts; (2) the emission probably originates in a small 'core' region in the very heart of a Seyfert nucleus; (3) synchrotron self-Compton radiation is the most plausible emission mechanism; and (4) Seyferts contribute 6 percent (plus or minus 3 percent) of the isotropic X-ray background radiation in the 2-10-keV band.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1978
- DOI:
- 10.1093/mnras/183.2.129
- Bibcode:
- 1978MNRAS.183..129E
- Keywords:
-
- Galactic Radiation;
- Luminous Intensity;
- Satellite Observation;
- Seyfert Galaxies;
- X Ray Sources;
- Ariel 5 Satellite;
- Spaceborne Astronomy;
- X Ray Astronomy;
- X Ray Density Measurement;
- Astrophysics;
- Seyfert Galaxies:X-Ray Sources