X-Ray Spectral Signatures of Very Thick Cold Matter in the Spectra of the Seyfert 1 Galaxies NGC 7469 and IC 4329A
Abstract
Observations with Ginga of the bright Seyfert 1 galaxies NGC 7469 and IC 4329A have revealed the presence of a hard X-ray bump above 8 keV. This new spectral component is probably produced by absorption or reflection of the central emission by a very thick (N_H_ > 10^24^ cm^- 2^) cold medium in the environment of the central source, possibly in an accretion disk. Detection of iron fluorescence lines at 6.4 keV with equivalent widths of 100-150 eV in both objects supports this scenario. The implications of these results on the spectral shape of the intrinsic X-ray continuum, the intensity of the soft X-ray excess in Seyfert galaxies, and the cosmic X-ray background are briefly pointed out.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1990
- DOI:
- 10.1086/185806
- Bibcode:
- 1990ApJ...360L..35P
- Keywords:
-
- Extraterrestrial Matter;
- Seyfert Galaxies;
- Spectral Signatures;
- X Ray Spectra;
- Accretion Disks;
- Background Radiation;
- Emission Spectra;
- Iron;
- X Ray Fluorescence;
- X Ray Sources;
- Astrophysics;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 7469;
- GALAXIES: INDIVIDUAL ALPHANUMERIC: IC 4329A;
- GALAXIES: SEYFERT;
- GALAXIES: X-RAYS