Related papers: X-rays from the First Massive Black Holes
We present X-ray and optical analysis of 188 AGN identified from 497 hard X-ray (f (2.0-8.0 keV) > 2.7x10^-15 erg cm^-2 s^-1) sources in 20 Chandra fields (1.5 deg^2) forming part of the Chandra Multi-wavelength Project. These medium depth…
We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and…
We studied bent radio sources within X-ray galaxy groups in the COSMOS and XMM-LSS fields, using radio data from the MeerKAT International GHz Tiered Extragalactic Explorations data release 1 (MIGHTEE-DR1) at 1.2-1.3 GHz (angular…
The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of…
Statistical studies of X-ray selected Active Galactic Nuclei (AGN) indicate that the fraction of obscured AGN increases with increasing redshift, and the results suggest that a significant part of the accretion growth occurs behind…
We present the results of a new analysis of the X-ray selected Active Galactic Nuclei (AGN) population in the vicinity of 135 of the most massive galaxy clusters in the redshift range of 0.2 < z < 0.9 observed with Chandra. With a sample of…
We explore host galaxy properties and environment of a sample of Type 1 and 2 active galactic nuclei (AGN) taken from the COSMOS2015 catalog, within 0.3 $\leq z \leq$ 1.1 selected for their emission in X-rays, optical spectra and SED…
Active galactic nuclei (AGN) are powerful sources of panchromatic radiation. All AGN emit in X-rays, contributing around $\sim 5-10\%$ of the AGN bolometric luminosity. The X-ray emitting region, popularly known as the corona, is…
The $\gamma$-ray emission from active galactic nuclei (AGN), including both beamed blazars and misaligned-AGN, dominates the extragalactic $\gamma$-ray point-source population count and flux. While multi-wavelength studies have detected an…
The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z<~1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a…
We perform long-term ($\approx 15$ yr, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms $Chandra$ Deep Field-South (CDF-S) survey; the majority are in the redshift range of…
We explore the connection between different classes of active galactic nuclei (AGNs) and the evolution of their host galaxies, by deriving host galaxy properties, clustering, and Eddington ratios of AGNs selected in the radio, X-ray, and…
Active galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales,…
First indications of the warm/hot intergalactic medium, tracing out the large scale structure of the universe, have been obtained in sensitive Chandra and XMM-Newton high resolution absorption line spectroscopy of bright blazars. High…
We study the incidence of nuclear obscuration on a complete sample of 1310 AGN selected on the basis of their rest-frame 2-10 keV X-ray flux from the XMM-COSMOS survey, in the redshift range 0.3<z<3.5. We classify the AGN as obscured or…
Many X-ray bright active galactic nuclei (AGN) are predicted to follow an extended stage of obscured black hole growth. In support of this picture we examine the X-ray undetected AGNs in the COSMOS field and compare their host galaxies with…
We use deep Chandra imaging and an extensive optical spectroscopy campaign on the Keck 10-m telescopes to study the properties of X-ray point sources in five large-scale structures at redshifts of z ~ 0.7-0.9. We first study X-ray point…
Most active galactic nuclei (AGN) lack prominent jets, and show modest radio emission and significant X-ray emission which arises mainly from the galactic core, very near from the central black hole. We use a quantitative scenario of such…
The X-ray and mid-IR emission from active galactic nuclei (AGN) are strongly correlated. However, while various published parameterizations of this correlation are consistent with the low-redshift, local Seyfert galaxy population,…
We study, by means of dedicated simulations of massive black hole build-up, the possibility to constraint the existence and nature of the AGN population at z>6 with available and planned X-ray and near infrared space telescopes. We find…