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Related papers: The Space Density of Compton Thick AGN and the X-r…

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We present the broad-band X-ray spectral analysis (0.6-50 keV) of seven Compton-Thick active galactic nuclei (CT-AGN; line-of-sight, l.o.s., column density $>10^{24}$ cm$^{-2}$) candidates selected from the Swift-BAT 100-month catalog,…

We compute the effect of the galactic absorption on AGN emission in a cosmological context by including a physical model for AGN feeding and feedback in a semi-analytic model of galaxy formation. This is based on galaxy interactions as…

Astrophysics · Physics 2009-11-13 N. Menci , F. Fiore , S. Puccetti , A. Cavaliere

The X-ray Background (XRB) probably originates from the integrated X-ray emission of active galactic nuclei (AGN). Modelling of its flat spectrum implies considerable absorption in most AGN. Compton down-scattering means that sources in…

Astrophysics · Physics 2009-10-31 A. C. Fabian , K. Iwasawa

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,…

In recent years deep X-ray and infrared surveys have provided an efficient way to find accreting supermassive black holes, otherwise known as active galactic nuclei (AGN), in the young universe. Such surveys can, unlike optical surveys,…

Astrophysics · Physics 2007-12-10 C. Megan Urry , E. Treister

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…

Astrophysics of Galaxies · Physics 2021-03-31 Mackenzie L Jones , K. Parker , G. Fabbiano , M. Elvis , W. P. Maksym , A. Paggi , J. Ma , M. Karovska , A. Siemiginowska , J. Wang

The massive black holes in most faint active galactic nuclei (AGNs) and even normal galaxies are still accreting gases, though their accretion rates are very low. Radiatively inefficient accretion flows (RIAFs) are supposed in these faint…

Astrophysics · Physics 2011-02-11 Xinwu Cao

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…

High Energy Astrophysical Phenomena · Physics 2025-02-03 Isaiah S. Cox , Núria Torres-Albà , Stefano Marchesi , Peter Boorman , Xiurui Zhao , Ross Silver , Marco Ajello , Indrani Pal

The Cosmic X-ray background carries the information of cosmic accretion onto super-massive black holes. The intensity at its peak can be used to constrain the integrated space density of highly obscured AGNs. Determining the shape and…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Marco Ajello

This work discusses the broadband X-ray spectral analysis of 11 candidate heavily-obscured active galactic nuclei (AGN) selected based on their infrared and X-ray properties by a recently published machine learning algorithm. This paper is…

(abridged)The majority of Active Galactic Nuclei (AGN) suffer from significant obscuration by surrounding dust and gas. X-ray surveys in the 2-10 keV band will miss the most heavily-obscured AGN in which the absorbing column density exceeds…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Stephanie M. LaMassa , Timothy M. Heckman , Andrew A. Ptak , Ann Hornschemeier , Lucimara Martins , Paule Sonnentrucker , Christy Tremonti

We use morphological information of X-ray selected AGN hosts to set limits on the fraction of the accretion density of the Universe at z~1 that is not likely to be associated with major mergers. Deep X-ray observations are combined with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 A. Georgakakis , A. L. Coil , E. S. Laird , R. L. Griffith , K. Nandra , J. M. Lotz , C. M. Pierce , M. C. Cooper , J. A. Newman , A. M. Koekemoer

Obscured AGN are fundamental to understand the history of Super Massive Black Hole growth and their influence on galaxy formation. However, the Compton-thick AGN (NH>1e24 cm^-2) population is basically unconstrained, with less than few…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 P. Severgnini , A. Caccianiga , R. Della Ceca , V. Braito , C. Vignali , V. La Parola , A. Moretti

We take advantage of the rich multi-wavelength data available in the Chandra Deep Field South (CDF-S), including the 4 Msec Chandra observations (the deepest X-ray data to date), in order to search for heavily-obscured low-luminosity AGN…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Ezequiel Treister , C. Megan Urry , Kevin Schawinski , Carolin N. Cardamone , David Sanders

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…

We present the 2-100 keV spectral analysis of 30 candidate Compton thick (CT-) active galactic nuclei (AGN) selected in the Swift-BAT 100-month survey. The average redshift of these objects is $\langle z\rangle\sim$0.03 and they all lie…

High Energy Astrophysical Phenomena · Physics 2018-02-21 Stefano Marchesi , Marco Ajello , Lea Marcotulli , Andrea Comastri , Giorgio Lanzuisi , Cristian Vignali

The local X-ray AGN population appears to follow a growth cycle regulated by the AGN's own radiation, marked by changes in their obscuration and Eddington ratio during accretion events. Because AGN in infrared-selected galaxies are more…

Due to their heavily obscured central engines, the growth rate of Compton-thick (CT) active galactic nuclei (AGN) is difficult to measure. A statistically significant correlation between the Eddington ratio, {\lambda}$_{Edd}$, and the X-ray…

High Energy Astrophysical Phenomena · Physics 2016-08-06 M. Brightman , A. Masini , D. R. Ballantyne , M. Baloković , W. N. Brandt , C. -T. Chen , A. Comastri , D. Farrah , P. Gandhi , F. A. Harrison , C. Ricci , D. Stern , D. J. Walton

The obscuration observed in active galactic nuclei (AGN) is mainly caused by dust and gas distributed in a torus-like structure surrounding the supermassive black hole (SMBH). However, properties of the obscuring torus of the AGN in X-ray…

Astrophysics of Galaxies · Physics 2021-06-09 X. Zhao , S. Marchesi , M. Ajello , D. Cole , Z. Hu , R. Silver , N. Torres-Albà

We present the X-ray analysis of the most luminous obscured active galactic nuclei (AGN) inside local ultraluminous infrared galaxies (ULIRGs). Our sample consists of ten sources, harbouring AGN components with estimated luminosity in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 E. Nardini , G. Risaliti