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X-ray fluorescent lines are unique features of the reflection spectrum of the cold torus when irradiated by the central AGN. Their intrinsic line widths can be used to probe the line-emitting region. The line widths of the Fe \Ka line…

High Energy Astrophysical Phenomena · Physics 2016-09-28 Jiren Liu

The cold disk/torus gas surrounding active galactic nuclei (AGN) emits fluorescent lines when irradiated by hard X-ray photons. The fluorescent lines of elements other than Fe and Ni are rarely detected due to their relative faintness. We…

High Energy Astrophysical Phenomena · Physics 2015-10-28 Weiwei Xu , Zhu Liu , Lijun Gou , Jiren Liu

The reflection spectrum of the torus around AGN is characterized by X-ray fluorescent lines, which are most prominent for type II AGN. A clumpy torus allows photons reflected from the back-side of the torus to leak through the front…

High Energy Astrophysical Phenomena · Physics 2016-04-06 Jiren Liu , Yuan Liu , Xiaobo Li , Weiwei Xu , Lijun Gou , Cheng Cheng

The location of the obscuring "torus" in an active galactic nucleus (AGN) is still an unresolved issue. The line widths of X-ray fluorescence lines originated from the torus, particularly Fe K$\alpha$, carry key information on the radii of…

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…

The 6.4 keV Fe Ka emission line is a ubiquitous feature in X-ray spectra of AGN, and its properties track the interaction between the variable primary X-ray continuum and the surrounding structure from which it arises. We clarify the nature…

X-ray line fluorescence is ubiquitous around powerful accretion sources, namely active galactic nuclei and X-ray binaries. The brightest and best-studied line is the Fe K$\alpha$ line at $\lambda = 1.937$\AA (6.4\,keV). This paper presents…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Roi Rahin , Ehud Behar

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…

High Energy Astrophysical Phenomena · Physics 2023-05-17 Jingzhe Ma , Martin Elvis , G. Fabbiano , Mislav Balokovic , W. Peter Maksym , Guido Risaliti

We analyze X-ray spectra of heavily obscured (N_H > 10^{24} cm^{-2}) active galaxies obtained with Chandra, concentrating on the iron K alpha fluorescence line. We measure very large equivalent widths in most cases, up to 5 keV in the most…

Astrophysics · Physics 2009-11-07 N. A. Levenson , J. H. Krolik , P. T. Zycki , T. M. Heckman , K. A. Weaver , H. Awaki , Y. Terashima

We present an X-ray spectral analysis of 126 galaxies of the 12 micron galaxy sample. We pay particular attention to Compton thick AGN with the help of new spectral fitting models that we have produced, which are based on Monte-Carlo…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Murray Brightman , Kirpal Nandra

In this paper we report on the broadband X-ray properties of a complete sample of 33 absorbed Seyfert galaxies hard X-ray selected with integral. The high quality broadband spectra obtained with both xmm, and integral-IBIS data are well…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-21 A. De Rosa , F. Panessa , L. Bassani , A. Bazzano , A. J. Bird , R. Landi , A. Malizia , M. Molina , P. Ubertini

We observed the Galactic black hole Cygnus X-1 with the Chandra High Energy Transmission Grating Spectrometer for 30 kiloseconds on 4 January, 2001. The source was in an intermediate state, with a flux that was approximately twice that…

We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations of 10 unique sources. We present…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Xinwen Shu , Tahir Yaqoob , Junxian Wang

Reprocessed X-ray emission in Active Galactic Nuclei (AGN) can provide fundamental information about the circumnuclear environments of supermassive black holes. Recent mid-infrared studies have shown evidence of an extended dusty structure…

High Energy Astrophysical Phenomena · Physics 2022-03-15 Carolina Andonie , Claudio Ricci , Stéphane Paltani , Patricia Arévalo , Ezequiel Treister , Franz Bauer , Marko Stalevski

We present the 0.5 - 50 keV Suzaku broad-band X-ray spectral study of the Compton-thick AGN in NGC 5135. The Suzaku observation provides the first detection of NGC 5135 above 10 keV that allowed us, for the first time, to estimate the…

High Energy Astrophysical Phenomena · Physics 2011-11-02 Veeresh Singh , Guido Risaliti , Valentina Braito , Prajval Shastri

Obscured AGNs provide an opportunity to study the material surrounding the central engine. Geometric and physical constraints on the absorber can be deduced from the reprocessed AGN emission. In particular, the obscuring gas may reprocess…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Raj Gohil , David R. Ballantyne

[Abridged]We report on the broadband X-ray properties of a complete sample of absorbed Seyfert galaxies hard X-ray selected with INTEGRAL. The sample is composed of 33 sources: 15 are newly discovered above 20 keV while 18 are already known…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 A. De Rosa , F. Panessa , L. Bassani , A. Bazzano , A. Bird , R. Landi , A. Malizia , M. Molina , P. Ubertini

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 analyze observations obtained with the Chandra X-ray Observatory of bright Compton thick active galactic nuclei (AGNs), those with column densities in excess of 1.5 x 10^{24} cm^{-2} along the lines of sight. We therefore view the…

Astrophysics · Physics 2011-07-21 N. A. Levenson , T. M. Heckman , J. H. Krolik , K. A. Weaver , P. T. Zycki

We detail the spectral analysis of a 170 ks XRISM Resolve observation of the core of Cygnus A. The high spectral resolution of Resolve have enabled us to probe the inner accretion region of Cygnus A by analyzing the 6.4 keV Fe K$\alpha$…

High Energy Astrophysical Phenomena · Physics 2026-05-19 Anwesh Majumder , T. Heckman , L. Gu , A. Simionescu , B. R. McNamara , A. Ptak , E. Hodges-Kluck , M. Yukita , M. W. Wise , N. Roy
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