Related papers: A Compton Thick AGN Powering the Hyperluminous Inf…
We report X-ray constraints for 20 of 52 high-z ULIRGs identified in the Spitzer xFLS to constrain their obscuration. Notably, decomposition of Spitzer-IRS spectra for the 52 objects already indicates that most are weak-PAH ULIRGs dominated…
Aims. We present a 0.2--200 keV broad-band study of absorbed AGN observed with INTEGRAL, XMM-Newton, Chandra and ASCA to investigate the continuum shape and the absorbing/reflecting medium properties. Methods. The sources are selected in…
We present X-ray spectral analyses for three Seyfert 2 active galactic nuclei, NGC 424, NGC 1320, and IC 2560, observed by NuSTAR in the 3-79 keV band. The high quality hard X-ray spectra allow detailed modeling of the Compton reflection…
Heavily obscured accretion is believed to represent an important stage in the growth of supermassive black holes, and to play an important role in shaping the observed spectrum of the Cosmic X-ray Background (CXB). Hard X-ray (E$>$10 keV)…
We investigate signs of Active Galactic Nucleus (AGN) in the luminous infrared galaxy NGC 3256 at both infrared and X-ray wavelengths. NGC 3256 has double, the Northern and Southern, nuclei (hereafter, N and S nuclei, respectively). We show…
The galaxy NGC 4418 contains one of the most compact obscured nuclei within a luminous infrared galaxy (LIRG) in the nearby Universe. This nucleus contains a rich molecular gas environment and an unusually high ratio of infrared to radio…
The Circinus galaxy is one of the nearest obscured AGN, making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN…
I present a review of X-ray and mid-IR surveys for Compton-thick Active Galactic Nuclei (AGN). These are the most highly obscured sources having hydrogen column densities >1.5x10^24 cm-2. Key surveys in the local Universe are presented…
We report the detection of rest--frame 6.2 and 7.7 \micron emission features arising from Polycyclic Aromatic Hydrocarbons (PAH) in the Spitzer/IRS spectrum of an infrared-luminous Lyman break galaxy at z=3.01. This is currently the highest…
Prominent Fe K line emission is detected at around 6.7 keV in the XMM-Newton spectrum of the ultraluminous infrared galaxy Arp220. The continuum emission in the 2.5-10 keV band is flat and a few other spectral features are suggested. The…
The Chandra component of the Great Observatories All-Sky LIRG Survey (GOALS) presently contains 44 luminous and ultraluminous infrared galaxies with log (Lir/Lsun) = 11.73-12.57. Omitting 15 obvious AGNs, the other galaxies are, on average,…
AGN exhibit complex hard X-ray spectra. Our current understanding is that the emission is dominated by inverse Compton processes which take place in the corona above the accretion disk, and that absorption and reflection in a distant…
We report the discovery of a Compton-thick Active Galactic Nucleus (AGN) at z=4.76 in the 4 Ms Chandra Deep Field South. This object was selected as a V-band dropout in HST/ACS images and previously recognized as an AGN from optical…
We present ROSAT HRI and ASCA observations of the well known ULIRG IRAS19254-7245 (the Superantennae). The object is not detected by ROSAT yielding a 3\sigma upper limit of L_x ~8x10^{41} erg/s in the 0.1-2 keV band. However, we obtain a…
Observation of the H2O megamaser galaxy IC 2560 with the Chandra Observatory reveals a complex spectrum composed of soft X-ray emission due to multi-temperature thermal plasma, and a hard continuum with strong emission lines. The continuum…
The Compton-thick Active Galactic Nuclei (AGN) arguably constitute the most elusive class of sources as they are absorbed by large column densities above logN_H(cm^-2)=24. These extreme absorptions hamper the detection of the central source…
We present the discovery of a reflection-dominated active galactic nucleus (AGN) in the early-type radio-quiet galaxy ESO 565--G019 with Suzaku and Swift/BAT. The source X-ray spectrum below 10 keV is characteristic of other Compton-thick…
We report the detection of the 6.4 keV Iron K{\alpha} emission line in two infrared-luminous, massive, star-forming BzK galaxies at z = 2.578 and z = 2.90 in the CDF-S. The Chandra 4 Ms spectra of BzK4892 and BzK8608 show a reflection…
We present the analysis of the XMM-Newton EPIC pn spectrum of the Seyfert 2 galaxy, Mrk3. We confirm that the source is dominated by a pure Compton reflection component and an iron K$\alpha$ line, both produced as reflection from a…
The narrow Fe K$\alpha$ line is one of the main signatures of the reprocessing of X-ray radiation from the material surrounding supermassive black holes, and it has been found to be omnipresent in the X-ray spectra of active galactic nuclei…