Related papers: Multi-wavelength Selected Compton-thick AGNs in Ch…
The majority of active galactic nuclei (AGN) are obscured by large amounts of absorbing material that makes them invisible at many wavelengths. X-rays, given their penetrating power, provide the most secure way for finding these AGN. The…
We present the spatial analysis of five Compton thick (CT) active galactic nuclei (AGNs), including MKN 573, NGC 1386, NGC 3393, NGC 5643, and NGC 7212, for which high resolution Chandra observations are available. For each source, we find…
We use a combination of the XMM-Newton serendipitous X-ray survey with the optical SDSS, and the infrared WISE all-sky survey in order to check the efficiency of the low X-ray to infrared luminosity selection method in finding heavily…
We briefly report here on our ongoing X-ray spectroscopy and variability analyses of 136 faint X-ray sources discovered in the 2 Ms Chandra Deep Field North observations spanning 1.4x10-15 to 2x10-13 ergs s-1 cm-2. Most sources are…
The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the…
We present the analysis of simultaneous NuSTAR and XMM-Newton data of 8 Compton-thick (CT-) active galactic nuclei (AGN) candidates selected in the Swift-Burst Alert Telescope (BAT) 100 month survey. This work is part of an ongoing effort…
Previous studies of the active galactic nuclei (AGN) contribution to the cosmic X-ray background (CXB) consider only observable parameters such as luminosity and absorbing column. Here, for the first time, we extend the study of the CXB to…
Kilo-parsec scale hard ($>$ 3 keV) X-ray continuum and fluorescent Fe K$\alpha$ line emission has been recently discovered in nearby Compton-thick (CT) active galactic nuclei (AGN), which opens new opportunities to improve AGN torus…
The obscured accretion phase in BH growth is a key ingredient in many models linking the AGN activity with the evolution of their host galaxy. At present, a complete census of obscured AGN is still missing. The purpose of this work is to…
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-thick Active Galactic Nuclei (AGNs) are ubiquitious at high redshift. However, few distant Compton-thick AGNs have been reliably identified…
We use Chandra data to study the incidence and properties of Active Galactic Nuclei (AGN) in 16 intermediate redshift ($0.5 < z < 1.1$) X-ray-selected galaxy groups in the Chandra Deep Field-South. We measure an AGN fraction of $f(L_{X,H} >…
In deep X-ray surveys, active galactic nuclei (AGNs) with a broad range of luminosities have been identified. However, cosmologically distant low-luminosity AGN (LLAGN, $L_{\mathrm{X}} \lesssim 10^{42}$ erg s$^{-1}$) identification still…
The all-sky hard X-ray survey performed by Swift/BAT allowed the detection of many heavily obscured Compton-thick AGN. In our previous work, we have identified more than 50 candidate Compton-thick AGN in the local Universe, corresponding to…
We perform X-ray spectral analyses to derive characteristics (e.g., column density, X-ray luminosity) of $\approx$10,200 active galactic nuclei (AGNs) in the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS), which was…
We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…
We present the results of the broadband X-ray spectral analysis of simultaneous NuSTAR and XMM-Newton observations of four nearby Compton-thick active galactic nuclei (AGN) candidates selected from the Swift-Burst Alert Telescope (BAT)…
We present the first results of the spectroscopy of distant, obscured AGN as obtained with the ultra-deep (~3.3 Ms) XMM-Newton survey in the Chandra Deep Field South (CDFS). One of the primary goals of the project is to characterize the…
In order to answer some of the major open questions in the fields of supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH growth, i.e., active galactic nuclei (AGN), is required. Thanks to deep all-sky surveys,…
Highly obscured active galactic nuclei (AGN) are common in nearby galaxies, but are difficult to observe beyond the local Universe, where they are expected to significantly contribute to the black hole accretion rate density. Furthermore,…
The efficiency of mid-infrared selection methods for finding obscured AGN is investigated using data in the \chandra Deep Field North. It is shown that samples of AGN candidates compiled on the basis of mid-infrared colours only suffer…