
We review some of the main physical and statistical properties of the X-ray absorber in AGNs. In particular, we review the distribution of the absorbing column density inferred from X-ray observations of various AGN samples. We discuss the location of the X-ray absorber and the relation with the dust absorption at optical and infrared wavelengths. Finally, we shortly review the recent findings on X-ray absorption at high luminosities and at high redshift.
10 pages, 4 figures, Conference proceedings to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP)
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
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