We use the clustering of galaxies around distant AGN to show with ∼ 90% confidence that fainter AGN are longer lived. Our argument is simple: since the measured galaxy-AGN cross-correlation length r0 ∼ 5h −1 Mpc does not vary significantly over a 10 magnitude range in AGN optical luminosity, faint and bright AGN must reside in dark matter halos with similar masses. The halos that host bright an...

Context. Feedback from accreting supermassive black holes is often identified as the main mechanism responsible for regulating star-formation in AGN host galaxies. However, the relationships between AGN activity, radiation, winds, and star-formation are complex and still far from being understood. Aims. We study scaling relations between AGN properties, host galaxy properties and AGN winds. We ...

Type 2 active galactic nuclei (AGN) represent the majority of the AGN population. However, due to the difficulties in measuring their black hole (BH) masses, it is still unknown whether they follow the same BH mass-host galaxy scaling relations valid for quiescent galaxies and type 1 AGN. Here we present the locus of type 2 AGN having virial BH mass estimates in the MBH − σ⋆ plane. Our analysis...

Increasing observational evidence supports a picture for a close link among AGN phenomenum, star-formation processes and galaxy formation. Since the physical phenomena related to the onset of both AGN and star formation are very likely characterized by a strong far infrared (FIR) emission it becomes mandatory to investigate the FIR energy domain. However, because of their faintness in the FIR e...

We present quantitative morphological analyses of 37 HST/WFPC2 counterparts of X-ray sources in the 1 Ms Chandra Deep Field–South (CDFS). We investigate: 1) one-dimensional surface brightness profiles via isophotal ellipse fitting; 2) two-dimensional, PSF-convolved, bulge+disk+nucleus profile-fitting; 3) asymmetry and concentration indices compared with all ∼ 3000 sources in our three WFPC2 fie...

From the earliest extragalactic infrared studies AGN have shown themselves to be strong infrared sources and IR surveys have revealed new populations of AGN. I briefly review current motivations for AGN surveys in the infrared and results from previous IR surveys. The Luminous Infrared Galaxies, which in some cases house dust-enshrouded AGN, submillimeter surveys, and recent studies of the cosm...

We present a study of the distribution of AGN in clusters of galaxies with a uniformly-selected, spectroscopically-complete sample of 35 AGN in eight clusters of galaxies at z = 0.06→ 0.31. We find that the 12 AGN with LX > 1042 erg s−1 in cluster members more luminous than a rest-frame MR < −20 mag are more centrally concentrated than typical cluster galaxies of this luminosity, although these...

Aims. We determine the cumulative spectral energy distribution of local AGN in the range 3–300 keV and compare it with the spectrum of the cosmic X-ray background (CXB) in order to test the widely accepted paradigm that the CXB is a superposition of active galactic nuclei (AGN) and to place constraints on AGN evolution. Methods. We perform a stacking analysis of the hard X-ray spectra of AGN de...

We combine optical and X-ray data for eight low redshift (z ∼ 0.06) poor groups of galaxies from the XI (XMM/IMACS) Groups Project to study the AGN population in the group environment. Among ∼ 140 group members, we identify five AGN based on their optical emission lines. None of these optically-selected AGN are detected by XMM-Newton. One additional AGN is discovered in the XMM-Newton observati...

We present a study of the distribution of AGN in clusters of galaxies with a uniformly selected, spectroscopically complete sample of 35 AGN in eight clusters of galaxies at z = 0.06 → 0.31. We find that the 12 AGN with LX > 1042 erg s−1 in cluster members more luminous than a rest-frame MR < −20 mag are more centrally concentrated than typical cluster galaxies of this luminosity, although thes...