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We present an exhaustive methodology for fitting Compton-thick X-ray reprocessor models to obscured AGNs and for interpreting the results. We focus on the MYTORUS model but also utilize other models. We apply the techniques to Suzaku,…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Tahir Yaqoob

We present an analysis of the X-ray properties of sources detected in the 13H XMM-Newton deep (200ks) field. In order to constrain the absorbed AGN population, we use extensive Monte Carlo simulations to directly compare the X-ray colours…

Astrophysics · Physics 2009-11-11 T. Dwelly , M. J. Page , N. S. Loaring , K. O. Mason , I. McHardy , K. Gunn , T. Sasseen

A complete census of Active Galactic Nuclei (AGN) is a prerequisite for understanding the growth of supermassive black holes across cosmic time. A significant challenge toward this goal is the whereabouts of heavily obscured AGN that remain…

Large column densities, derived from X-ray studies, are typically measured towards AGN hosting water masers, especially when the H2O emission is associated with the nuclear accretion disk. In addition, possible correlations between the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 P. Castangia , F. Panessa , C. Henkel , M. Kadler , A. Tarchi

We have determined the cosmological evolution of the density of AGN and of their Nh distribution as a function of the un-absorbed 2-10 keV luminosity up to redshift 4. We used the HELLAS2XMM sample combined with other published catalogs,…

The X-ray spectra of active galactic nuclei (AGN) unveil properties of matter around the super massive black hole (SMBH). We investigate the X-ray spectra of AGN focusing on Compton reflection and fluorescence, important processes of…

Astrophysics of Galaxies · Physics 2014-08-12 S. Falocco , F. J. Carrera , X. Barcons , G. Miniutti , A. Corral

We present X-ray spectral analysis of the brightest sources (f_{2-10 keV}>10^{-15}$ cgs) in the Chandra Deep Field North. Our sample consists of 222 sources; for the vast majority (171) either a spectroscopic or a photometric redshift is…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 I. Georgantopoulos , A. Akylas , A. Georgakakis , M. Rowan-Robinson

The 2-10 keV continuum of AGN is well represented by a single power law, generally attributed to a hot comptonizing medium, such as a corona above the accretion disk. At smaller energies the continuum displays an excess with respect to the…

We analyse Compton-thick active galactic nuclei (CT AGNs), a heavily obscured subclass that challenges traditional X-ray diagnostics. Using 243 sources from the 70-Month \textit{SWIFT}/BAT catalogue (26 CT, 217 non-CT), we investigate their…

Our understanding of highly accreting AGNs is hampered by the lack of a complete systematic investigation in terms of their main spectral and variability properties, and by the relative paucity of them in the local Universe, especially…

High Energy Astrophysical Phenomena · Physics 2024-09-25 M. Laurenti , F. Tombesi , F. Vagnetti , E. Piconcelli , M. Guainazzi , C. Vignali , M. Paolillo , R. Middei , A. Bongiorno , L. Zappacosta

We present the multi-epoch monitoring with NuSTAR and XMM-Newton of NGC 1358, a nearby Seyfert 2 galaxy whose properties made it a promising candidate X-ray changing look AGN, i.e., a source whose column density could transition from its…

Understanding the radiative and physical structures of inner region of a few 100 pc of AGNs is important to constrain the causes of their activities. Although the X-ray emission from the Comptonization region/corona and the accretion disc…

High Energy Astrophysical Phenomena · Physics 2021-12-22 K. Sriram , D. Nour , C. S. Choi

The nature of the broad-band spectra of supermassive accreting black holes in active galactic nuclei (AGNs) is still unknown. The hard X-ray spectra of Seyferts as well as of Galactic stellar-mass black holes (GBHs) are well represented by…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Alexandra Veledina , Indrek Vurm , Juri Poutanen

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…

High Energy Astrophysical Phenomena · Physics 2017-08-02 L. Baronchelli , M. Koss , K. Schawinski , C. Cardamone , F. Civano , A. Comastri , M. Elvis , G. Lanzuisi , S. Marchesi , C. Ricci , M. Salvato , B. Trakhtenbrot , E. Treister

Accreting supermassive black holes (SMBHs), also known as active galactic nuclei (AGN), are generally surrounded by large amounts of gas and dust. This surrounding material reprocesses the primary X-ray emission produced close to the SMBH…

By comparing an optically selected sample of narrow lines AGN with an X-ray selected sample of AGN we have recently derived an estimate of the intrinsic (i.e. before absorption) 2-10 keV luminosity function (XLF) of Compton Thick AGNs. We…

Astrophysics of Galaxies · Physics 2009-06-25 R. Della Ceca , A. Caccianiga , P. Severgnini

A simple model for the X-ray weakness of JWST-selected broad-line AGNs is proposed under the assumption that the majority of these sources are fed at super-Eddington accretion rates. In these conditions, the hot inner corona above the…

Astrophysics of Galaxies · Physics 2024-11-12 Piero Madau , Francesco Haardt

The X-ray spectra of many active galactic nuclei (AGN) show a soft X-ray excess below 1-2 keV on top of the extrapolated high- energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred,…

High Energy Astrophysical Phenomena · Physics 2018-03-28 P. O. Petrucci , F. Ursini , A. De Rosa , S. Bianchi , M. Cappi , G. Matt , M. Dadina , J. Malzac

We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS) taking advantage of optical spectroscopy and photometric redshifts for 321 sources. As a default spectral model, we adopt…

We study the X-ray properties of a sample of 14 optically-selected low-mass AGN whose masses lie within the range 1E5 -2E6 M(solar) with XMM-Newton. Only six of these low-mass AGN have previously been studied with sufficient quality X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-23 R. M. Ludlam , E. M. Cackett , K. Gultekin , A. C. Fabian , L. Gallo , G. Miniutti
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