Mass without radiation: Heavily obscured AGNs, the X-ray background, and the black hole mass density
Journal
Date Issued
2015
Author(s)
Description
This work was partially supported by the ASI/INAF I/037/12/0–011/13, the PRIN–INAF–2011 and the PRIN–INAF–2012 grants. We thank Marcella Brusa, Marco Mignoli and Gianni Zamorani for useful discussions, and the anonymous referee for constructive comments. A.C. acknowledges the support of a Caltech Kingsley visitor fellowship.
Abstract
A recent revision of black hole scaling relations indicate that the local mass density in black holes should be five times higher than previously determined values. The local black hole mass density is connected to the mean radiative efficiency of accretion through the time integral of the Active Galactic Nuclei (AGN) volume density and a significant increase in the local black hole mass density would have interesting consequences on AGN accretion properties and demography. One possibility to explain a large black hole mass density is that most of the black hole growth is via radiatively inefficient channels such as super Eddington accretion; however, this solution is not unique. Here we show how it is possible to accommodate a larger fraction of heavily buried, Compton-thick AGNs, without violating the limit imposed by the spectral energy density of the hard X-ray and mid-infrared backgrounds.
Volume
574
Start page
L10
Issn Identifier
0004-6361
Ads BibCode
2015A&A...574L..10C
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
aa25496-14(1).pdf
Size
206.7 KB
Format
Adobe PDF
Checksum (MD5)
9afd3c067614c17f13d94e3d207da985