2006/11/21 by F. Marulli, E. Branchini, L. Moscardini +2 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.11329.x
published as Mon.Not.Roy.Astron.Soc.375:649-656,2007 · 8 pages, 4 figures. Accepted by MNRAS
arxiv created 2006/11/21 · openalex publication_date 2007/01/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/29
We consider simple semi-analytic models that relate the active galactic nuclei (AGNs) evolution to the merging history of their host dark matter haloes and quantify their ability of matching the AGN luminosity function (LF) and its spatial clustering at low and intermediate redshifts. In particular, we focus on the recent determinations of the AGN LF in the hard X-ray band at z∼ 0 which constitutes the most stringent observational test for our models. Indeed, while we find an acceptable agreement between the model bolometric LF and the data at 1 ≲z≤ 2 and for luminosities larger then 1010 L bol,⊙, no semi-analytic model is capable of reproducing the number density of faint X-ray sources in the local universe. Some improvement can be obtained by advocating energy feedback that we model through a time-dependent Eddington ratio. Even in this case, however, the number density of faint AGNs is significantly below observations. This failure indicates that major mergers cannot constitute the only trigger to accretion episodes in the local AGN population.