Effect of X-ray spectra of Seyfert galaxies on the cosmic X-ray background.
Abstract
Ginga observations of five Seyfert 1 galaxies have revealed that their X-ray spectra are not described by a single power law, but have an absorption-like feature at the energy of several to 10 keV and flatten at higher energies. This spectrum may be explained by the absorption of very thick cold matter with a column density of the order of 10^24^-10^25^ cm^-2^ covering about half of the central source. We find that the superposition of such spectra can reproduce the 3-100 keV spectrum of the cosmic X-ray background (XRB) provided that the spectra of Seyfert galaxies have an exponential cut off around 100 keV. If most Seyfert galaxies and quasars have such spectra and undergo the same cosmological evolution, we can explain both the observed log N - log S relation of AGNs and the intensity and fluctuation of the XRB.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1990
- Bibcode:
- 1990A&A...236..299M
- Keywords:
-
- Background Radiation;
- Cosmic X Rays;
- Seyfert Galaxies;
- X Ray Spectra;
- Absorption Spectra;
- Active Galactic Nuclei;
- Luminosity;
- Astrophysics