Properties of the circumnuclear medium in Active Galactic Nuclei
Abstract
We propose a classification scheme for the circumnuclear medium of AGNs based on their location in the A_V - N_H plane (related to dust absorption and gas absorption, respectively). We present evidence that the A_V/N_H ratio is often lower than the Galactic value. This is shown by the broad line ratios of a sample of intermediate Seyferts, and by the optical/X-ray ratio of line selected (as opposed to color selected) AGNs. We point out the implications for the physical properties of the absorber. A complete classification would require a third axis, related to the density of the absorber and/or its distance from the AGN.
Keywords
Cite
@article{arxiv.astro-ph/0103077,
title = {Properties of the circumnuclear medium in Active Galactic Nuclei},
author = {R. Gilli and G. Risaliti and P. Severgnini and R. Maiolino and A. Marconi and M. Salvati},
journal= {arXiv preprint arXiv:astro-ph/0103077},
year = {2007}
}
Comments
6 LaTeX pages including 5 postscript figures; to appear in the Proceedings of ``X-ray Astronomy 2000'', R. Giacconi, L. Stella & S. Serio Eds., ASP Conf. Series