X-ray properties of active galaxies with high intrinsic absorption.
Abstract
We present the results of Ginga observations of three narrow emission line X-ray galaxies, NGC 7172, NGC 7582 and ESO 103-G35. In each of these galaxies the column density along the line of sight to the active nucleus is extremely high (i.e. n_H_ ~> 10^23^ cm^-2^). A comparison of the optical depth in the iron K-edge with the low-energy absorption in the X- ray spectrum indicates an apparent iron abundance in excess of the solar value in these sources. Measurements of the iron K-edge energy show that the bulk of the X-ray-absorbing gas is not strongly photoionized, with only ESO 103-G35 exhibiting an edge energy significantly above that for neutral iron. In the case of NGC 7582, the line-of-sight column density may have increased by a factor of ~3 over an interval of about 4 yr. The implications of these results for current models of the state and distribution of gaseous material in low-luminosity active galactic nuclei are briefly discussed.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 1993
- DOI:
- Bibcode:
- 1993MNRAS.265..412W
- Keywords:
-
- X Ray Sources;
- X Ray Spectra;
- Line Spectra;
- Active Galactic Nuclei;
- Abundance;
- Iron;
- Astronomical Models;
- Spectrum Analysis;
- Astrophysics