Related papers: Are Compton-thin AGNs Globally Compton Thin?
The X-ray spectra of Active Galactic Nuclei (AGN) carry the signatures of the emission from the central region, close to the Super Massive Black Hole (SMBH). For this reason, the study of deep X-ray spectra is a powerful instrument to…
Extremely strong ionized Fe emission lines, with the equivalent width reaching about 4000 eV, were discovered with ASCA from a few Galactic compact objects, including AX J2315-0592, RX J1802.1+1804 and AX J1842.8-0423. These objects are…
The 70-month Swift/BAT catalogue provides a sensitive view of the extragalactic X-ray sky at hard energies (>10 keV) containing about 800 Active Galactic Nuclei. We explore its content in heavily obscured, Compton-thick AGN by combining the…
Through an optical campaign performed at 5 telescopes located in the northern and the southern hemispheres, plus archival data from two on line sky surveys, we have obtained optical spectroscopy for 17 counterparts of suspected or poorly…
Reprocessed X-ray radiation from active galactic nuclei (AGN) carries important information about the properties of the circumnuclear material around the black hole. The X-ray photons travel from the very center of the system and interact…
We performed near-diffraction-limited (~0.4 FWHM) N-band imaging of one of the nearest Active Galactic Nucleus (AGN) in M51 with 8.2m Subaru telescope to study the nuclear structure and spectral energy distribution (SED) at 8-13 um. We…
To fully understand cosmic black hole growth we need to constrain the population of heavily obscured active galactic nuclei (AGN) at the peak of cosmic black hole growth ($z\sim$1-3). Sources with obscuring column densities higher than…
We analyzed the spectral shape of the Compton shoulder around the neutral Fe-K$_\alpha$ line of the Compton-thick type II Seyfert nucleus of the Circinus galaxy. The characteristics of this Compton shoulder with respect to the reflected…
We present new data for four candidate obscured Compton-Thick (CT) quasars at z $\sim$1-2.5 observed with SINFONI VLT spectrograph in AO mode. These sources were selected from a 24$\mu$m Spitzer MIPS survey of the COSMOS field, on the basis…
The Chandra Deep Field is the region of the sky with the highest concentration of X-ray data available: 4Ms of Chandra and 3Ms of XMM data, allowing excellent quality spectra to be extracted even for faint sources. We take advantage of this…
We present an analysis of five Suzaku observations of the bright Seyfert1 galaxy IC 4329A. The broad energy band and high signal-to-noise ratio of the data give new constraints on the iron K alpha line profile and its relationship with the…
Monte Carlo simulation is one of the best tools to study the complex spectra of Compton-thick AGNs and to figure out the relation between their nuclear structures and X-ray spectra. We have simulated X-ray spectra of Compton-thick AGNs…
We present a deep Chandra spectral and spatial study of the kpc-scale diffuse X-ray emission of the Compton thick (CT) AGN ESO428-G014. The entire spectrum is best fit with composite photoionization + thermal models. The diffuse emission is…
We present a rest-frame spectral stacking analysis of ~1000 X-ray sources detected in the XMM-COSMOS field in order to investigate the iron K line properties of active galaxies beyond redshift z~1. In Type I AGN that have a typical X-ray…
There is clear evidence that the $\gamma$-ray emission from active galactic nuclei (AGNs) is attributed to the inverse Compton scatterings in the relativistic blobs near the massive black holes. If the soft seed photons are from the regions…
Mrk 590 is a Changing Look AGN currently in an unusual repeat X-ray and UV flaring state. Here, we report on deep X-ray observations with XMM-Newton, NuSTAR, and NICER, obtained at a range of X-ray flux levels. We detect a prominent soft…
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 study the NH distribution in a complete sample of 88 AGN selected in the 20-40 keV band from INTEGRAL/IBIS observations. We find that the fraction of absorbed (NH > 10^{22} cm^2) sources is 43% while the Compton thick AGN comprise 7% of…
We present the results of a systematic analysis of Fe K emission lines in low-luminosity AGNs (LLAGNs) observed with ASCA. We used a sample of LLAGNs with small intrinsic absorption to compare with luminous AGNs and accretion models. Some…
We present results from a 150 ksec Suzaku observation of the Seyfert 1.5 NGC 3516 in October 2005. The source was in a relatively highly absorbed state. Our best-fit model is consistent with the presence of a low-ionization absorber which…