X-RAY-PROPERTIES OF ACTIVE GALAXIES WITH HIGH INTRINSIC ABSORPTION

Citation
Rs. Warwick et al., X-RAY-PROPERTIES OF ACTIVE GALAXIES WITH HIGH INTRINSIC ABSORPTION, Monthly Notices of the Royal Astronomical Society, 265(2), 1993, pp. 412-420
Citations number
52
Categorie Soggetti
Astronomy & Astrophysics
ISSN journal
00358711
Volume
265
Issue
2
Year of publication
1993
Pages
412 - 420
Database
ISI
SICI code
0035-8711(1993)265:2<412:XOAGWH>2.0.ZU;2-T
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 th ese galaxies the column density along the line of sight to the active nucleus is extremely high (i.e. n(H) greater-than-or-similar-to 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 g as is not strongly photoionized, with only ESO 103-G35 exhibiting an e dge energy significantly above that for neutral iron. In the case of N GC7582, the line-of-sight column density may have increased by a facto r of approximately 3 over an interval of about 4 yr. The implications of these results for current models of the state and distribution of g aseous material in low-luminosity active galactic nuclei are briefly d iscussed.