Where are the type 2 AGNs?
Astrophysics
2007-05-23 v1
Abstract
Most of the energy of the X-ray background is contributed by sources with a hard X-ray spectrum, harder than the spectrum observed in nearby type 1 AGNs. The hard background contributors are conventionally identified with type 2 AGNs, obscured by circumnuclear matter both in the optical and in the soft X rays. However, preliminary results of identification programs seem to find systematically few type 2 AGNs in samples selected with obscuration insensitive criteria. We discuss this issue, and assess the various scenarios which are being proposed to solve the discrepancy.
Keywords
Cite
@article{arxiv.astro-ph/0001332,
title = {Where are the type 2 AGNs?},
author = {M. Salvati and R. Maiolino},
journal= {arXiv preprint arXiv:astro-ph/0001332},
year = {2007}
}
Comments
To appear in the proceedings of the conference "Large Scale Structure in the X-ray Universe", Santorini, Greece, September 1999, 4 pages, 2 figures