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The geometry of the dust distribution within the inner regions of Active Galactic Nuclei (AGN) is still a debated issue and relates directly with the AGN unified scheme. Traditionally, models discussed in the literature assume one of two…

宇宙学与河外天体物理 · 物理学 2015-06-05 A. Feltre , E. Hatziminaoglou , J. Fritz , A. Franceschini

Several models of nuclear dust in active galactic nuclei (AGN) have been presented in the literature to determine its physical and geometrical properties, usually assuming the dust density distribution as the main aspect producing…

Over ten mid-infrared (mid-IR) and X-ray models are currently attempting to describe the nuclear obscuring material of active galactic nuclei (AGNs), but many questions remain unresolved. This study aims to determine the physical parameters…

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to type 1 line spectrum for pole-on viewing and type 2 characteristics in edge-on sources. Infrared radiation at its…

天体物理学 · 物理学 2007-05-23 Moshe Elitzur , Maia Nenkova , Zeljko Ivezic

The dusty environments (= "dust tori'') of AGN are now in reach of observations. Following our paper I on ground-based mid-IR spectro-photometry (H\"onig et al. 2010), we present an upgrade to our radiative transfer model of 3-dimensional…

宇宙学与河外天体物理 · 物理学 2015-05-14 S. F. Hoenig , M. Kishimoto

From extensive radiative transfer calculations we find that clumpy torus models with \No \about 5--15 dusty clouds along radial equatorial rays successfully explain AGN infrared observations. The dust has standard Galactic composition, with…

天体物理学 · 物理学 2011-02-11 Maia Nenkova , Matthew M. Sirocky , Robert Nikutta , Zeljko Ivezic , Moshe Elitzur

According to unified schemes of Active Galactic Nuclei (AGN), the central engine is surrounded by dusty, optically thick clouds in a toroidal structure. We have recently developed a formalism that for the first time takes proper account of…

天体物理学 · 物理学 2009-11-13 Maia Nenkova , Matthew M. Sirocky , Zeljko Ivezic , Moshe Elitzur

Dust reprocesses the intrinsic radiation of active galactic nuclei (AGNs) to emerge at longer wavelengths. The observed mid-infrared (MIR) luminosity depends fundamentally on the luminosity of the central engine, but in detail it also…

宇宙学与河外天体物理 · 物理学 2015-05-13 N. A. Levenson , J. T. Radomski , C. Packham , R. E. Mason , J. J. Schaefer , C. M. Telesco

The AGN-heated dust distribution (the "torus") is increasingly recognized not only as the absorber required in unifying models, but as a tracer for the reservoir that feeds the nuclear Super-Massive Black Hole. Yet, even its most basic…

We assume that dust near active galactic nuclei (AGN) is distributed in a torus-like geometry, which may be described by a clumpy medium or a homogeneous disk or as a combination of the two (i.e. a 2-phase medium). The dust particles…

星系天体物理 · 物理学 2015-11-11 Ralf Siebenmorgen , Frank Heymann , Andreas Efstathiou

An integral part of the Unified Model for Active Galactic Nuclei (AGNs) is an axisymmetric obscuring medium, which is commonly depicted as a torus of gas and dust surrounding the central engine. However, a robust, dynamical model of the…

宇宙学与河外天体物理 · 物理学 2015-06-04 S. K. Keating , J. E. Everett , S. C. Gallagher , R. P. Deo

We use mid-infrared spectral decomposition to separate the 6micron mid-infrared AGN continuum from the host emission in the ISO low resolution spectra of 71 active galaxies and compare the results to observed and intrinsic 2-10keV hard…

天体物理学 · 物理学 2009-11-10 D. Lutz , R. Maiolino , H. W. W. Spoon , A. F. M. Moorwood

We investigate the emission of active galactic nuclei (AGN) dusty tori in the infrared domain. Following theoretical predictions coming from hydrodynamical simulations, we model the dusty torus as a 3D two-phase medium with high-density…

宇宙学与河外天体物理 · 物理学 2012-02-29 Marko Stalevski , Jacopo Fritz , Maarten Baes , Theodoros Nakos , Luka C. Popovic

Warm gas and dust surround the innermost regions of active galactic nuclei (AGN). They provide the material for accretion onto the super-massive black hole and they are held responsible for the orientation-dependent obscuration of the…

宇宙学与河外天体物理 · 物理学 2015-06-04 K. R. W. Tristram , M. Schartmann , L. Burtscher , K. Meisenheimer , W. Jaffe , M. Kishimoto , S. F. Hönig , G. Weigelt

We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust…

天体物理学 · 物理学 2009-11-13 J. Fritz , A. Franceschini , E. Hatziminaoglou

A cornerstone of AGN unification schemes is the presence of an optically and geometrically thick dust torus. It provides the obscuration to explain the difference between type 1 and type 2 AGN. We investigate the influence of the dust…

天体物理学 · 物理学 2007-09-24 Sebastian F. Hoenig , Thomas Beckert

Recent observations of NGC 1068 and other AGN support the idea of a geometrically and optically thick dust torus surrounding the central supermassive black hole and accretion disk of AGN. In type 2 AGN, the torus is seen roughly edge-on,…

天体物理学 · 物理学 2007-05-23 S. F. Hoenig , T. Beckert , K. Ohnaka , G. Weigelt

We present the results of a systematic, broadband X-ray spectral analysis of nearby active galactic nuclei (AGNs) with the X-ray clumpy torus model (XCLUMPY; Tanimoto et al. 2019). By adding 16 AGNs newly analyzed in this paper, we study…

高能天体物理现象 · 物理学 2021-01-20 Shoji Ogawa , Yoshihiro Ueda , Atsushi Tanimoto , Satoshi Yamada

We present a statistical analysis of the properties of the obscuring material around active galactic nuclei (AGN). This study represents the first of its kind for an ultra-hard X-ray (14-195keV; Swift/BAT) volume-limited (DL<40 Mpc) sample…

The primary source of emission of active galactic nuclei (AGN), the accretion disk, is surrounded by an optically and geometrically thick dusty structure ("the so-called dusty torus"). The infrared radiation emitted by the dust is nothing…

星系天体物理 · 物理学 2017-01-13 Marko Stalevski , Claudio Ricci , Yoshihiro Ueda , Paulina Lira , Jacopo Fritz , Maarten Baes
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