Soft X-ray spectral observations of quasars and high X-ray luminositySeyfert galaxies.
Abstract
Results of the analysis of 28 Einstein SSS observations of 15 high X-ray luminosity (L(x) 10 to the 435 power erg/s) quasars and Seyfert type 1 nuclei are presented. The 0.75-4.5 keV spectra are in general well fit by a simple model consisting of a power law plus absorption by cold gas. The average spectral index alpha is 0.66 + or -0.36, consistent with alpha for the spectrum of these objects above 2 keV. In all but one case, no evidence was found for intrinsic absorption, with an upper limit of 2 x 10 to the 21st power/sq cm. Neither was evidence found for partial covering of the active nucleus by dense, cold matter (NH greater than 10 to the 22nd power/sq cm); the average upper limit on the partial covering fraction is 0.5. There is no obvious correlation between spectral index and 0.75-4.5 keV X-ray luminosity (which ranges from 3 x 10 to the 43rd to 47th powers erg/s) or with other source properties. The lack of intrinsic X-ray absorption allows us to place constraints on the density and temperature of the broad-line emission region, and narrow line emission region, and the intergalactic medium. Previously announced in STAR as N84-14082
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1984
- DOI:
- 10.1086/162018
- Bibcode:
- 1984ApJ...280..499P
- Keywords:
-
- Galactic Nuclei;
- Luminosity;
- Quasars;
- Seyfert Galaxies;
- X Ray Spectra;
- Emission Spectra;
- Heao 2;
- Intergalactic Media;
- Line Spectra;
- X Ray Astronomy;
- X Ray Sources;
- Astrophysics