Warm absorbers in active galactic nuclei: A multitemperature wind

被引:216
作者
Krolik, JH [1 ]
Kriss, GA
机构
[1] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA
[2] Space Telescope Sci Inst, Baltimore, MD 21218 USA
关键词
galaxies : active; galaxies : nuclei; galaxies : Seyfert; quasars : absorption lines; ultraviolet : galaxies; X-rays : galaxies;
D O I
10.1086/323442
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Although soft X-ray absorption features in AGNs were discovered almost ten years ago, the nature and location of the gas creating them has remained controversial. Guided by the results of recent high-resolution X-ray spectroscopy, we argue that these features are created in a multitemperature wind whose source of matter is photoionized evaporation from the inner edge of the obscuring torus often found surrounding an AGN. Photoionized evaporation in the presence of a copious mass source locks the ratio of ionizing intensity to pressure to a critical value. However, a broad range of temperatures can coexist in equilibrium for this value of the ratio of ionizing intensity to pressure. Consequently, the flow is expected to be strongly inhomogeneous in temperature. The inferred distance of this material from the source of ionizing radiation depends on how much matter exists at the highest obtainable temperature. This distance can be measured by monitoring how ionic column densities respond to changes in the ionizing continuum on timescales of days to years.
引用
收藏
页码:684 / 690
页数:7
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