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相关论文: An X-ray spectral model for clumpy tori in active …

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The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of…

天体物理学 · 物理学 2009-11-07 Belinda J. Wilkes , Gary D. Schmidt , Roc M. Cutri , Himel Ghosh , Dean C. Hines , Brant Nelson , Paul Smith

Near- and mid-infrared interferometers have resolved the dusty parsec-scale obscurer (torus) around nearby active galactic nuclei (AGNs). With the arrival of extremely large single-aperture telescopes, the emission morphology will soon be…

星系天体物理 · 物理学 2021-10-13 R. Nikutta , E. Lopez-Rodriguez , K. Ichikawa , N. A. Levenson , C. Packham , S. F. Hönig , A. Alonso-Herrero

We present a thorough study of the Changing-Look Active Galactic Nucleus (CL-AGN) Mrk 1018, utilizing an extensive dataset spanning optical, UV, and X-ray spectro-photometric data from 2005 to 2019. We analysed X-ray spectra and broad-band…

高能天体物理现象 · 物理学 2023-12-14 S. Veronese , C. Vignali , P. Severgnini , G. A. Matzeu , M. Cignoni

Only a small fraction of galactic nuclei in the nearby universe are luminous; most of them are currently dim. We investigate the feasibility of constraining the X-ray luminosity in the recent past (up to ~10^6 years ago) of the nucleus of a…

天体物理学 · 物理学 2009-11-07 S. Sazonov , R. Sunyaev , C. Cramphorn

This is the second in a series of papers devoted to explore a set of six dusty models of active galactic nuclei (AGN) with available spectral energy distributions (SEDs). These models are the smooth torus by Fritz et al. (2006), the clumpy…

Surveys of Active Galactic Nuclei (AGN) in different observational regimes seem to give different answers for the behaviour of the obscured fraction with luminosity. Based on the complex spectra seen in recent studies, we note that partial…

宇宙学与河外天体物理 · 物理学 2015-06-16 Jack H. Mayo , Andy Lawrence

Most of the optically classified low ionisation narrow emission-line regions (LINERs) nuclei host an active galactic nuclei (AGN). However, how they fit into the unified model (UM) of AGN is still an open question. The aims of this work are…

Many nearby AGNs display a significant short-term variability. In this work we re-analyze photometric data of four active galactic nuclei observed by Kepler in order to study the flickering activity, having as main goal that of searching…

星系天体物理 · 物理学 2017-07-26 A. Dobrotka , V. Antonuccio-Delogu , I. Bajcicakova

The variability of the X-ray spectra of active galactic nuclei (AGN) usually includes a change of the spectral slope. This has been investigated for a small sample of local AGNs by Sobolewska and Papadakis, who found that slope variations…

星系天体物理 · 物理学 2016-03-23 Roberto Serafinelli , Fausto Vagnetti , Riccardo Middei

Context: Active galactic nuclei (AGN) are anisotropic objects surrounded by an optically thick equatorial medium whose true geometry still defy observers. Aims: In this paper, we aim to explore the optical, scattering-induced, polarization…

星系天体物理 · 物理学 2017-11-15 F. Marin , M. Schartmann

The X-ray spectra of active galactic nuclei (AGNs) often exhibit an excess of emission above the primary power-law at energies <~ $2$ keV. Two models for the origin of this `soft excess' are ionized relativistic reflection from the inner…

高能天体物理现象 · 物理学 2022-06-22 Xin Xiang , D. R. Ballantyne , S. Bianchi , A. De Rosa , G. Matt , R. Middei , P. -O. Petrucci , A. Rozanska , F. Ursini

Short-term variability of X-ray spectra has been reported for several Active Galactic Nuclei. Significant X-ray flux variations are observed within time scales down to 10^4 -- 10^5 seconds. We discuss short variability time scales in the…

天体物理学 · 物理学 2007-05-23 R. W. Goosmann , B. Czerny , A. -M. Dumont , M. Mouchet , A. Rozanska , V. Karas , M. Dovciak

Recent evidence for a strong 'hard excess' of flux at energies > 20 keV in some Suzaku observations of type 1 Active Galactic Nuclei (AGN) has motivated an exploratory study of the phenomenon in the local type 1 AGN population. We have…

高能天体物理现象 · 物理学 2015-06-12 M. M. Tatum , T. J. Turner , L. Miller , J. N. Reeves

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…

星系天体物理 · 物理学 2014-08-12 S. Falocco , F. J. Carrera , X. Barcons , G. Miniutti , A. Corral

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…

高能天体物理现象 · 物理学 2015-10-28 Weiwei Xu , Zhu Liu , Lijun Gou , Jiren Liu

[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…

宇宙学与河外天体物理 · 物理学 2015-06-03 A. De Rosa , F. Panessa , L. Bassani , A. Bazzano , A. Bird , R. Landi , A. Malizia , M. Molina , P. Ubertini

Active Galactic Nuclei (AGN) are perfect laboratories to check General Relativity (GR) effects by using Broad Line Region (BLR) clouds eclipses to probe the innermost regions of the accretion disk. A new relativistic X-ray spectral model…

星系天体物理 · 物理学 2016-12-23 Mario Sanfrutos , Giovanni Miniutti

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…

星系天体物理 · 物理学 2017-02-01 Youichi Ohyama , Satoki Matsushita , Nagisa Oi , Ai-Lei Sun

We report on the Imaging X-ray Polarimetry Explorer (IXPE) observation of the closest and X-ray brightest Compton-thick active galactic nucleus (AGN), the Circinus galaxy. We find the source to be significantly polarized in the 2--6 keV…

Active galactic nuclei (AGN) show evidence for reprocessing gas, outflowing from the accreting black hole. The combined effects of absorption and scattering from the circumnuclear material likely explains the `hard excess' of X-ray emission…

高能天体物理现象 · 物理学 2016-02-17 M. M. Tatum , T. J. Turner , L. Miller , J. N. Reeves , J. DiLiello , J. Gofford , A. Patrick , M. Clayton
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