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The putative dusty torus is a key ingredient of the unification scheme of active galactic nuclei (AGN), but its origin remains a mystery. Here we put forward a new physical model to explain how a large number of small dusty gas clumps form…

星系天体物理 · 物理学 2026-03-09 Xinwu Cao , Renyue Cen , Qingwen Wu , Jiancheng Wu

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

We discuss the question whether the matter in dusty tori around active galactic nuclei has a smooth or a clumpy structure. Nenkova, Ivezic & Elitzur (2002) have argued that the lack of emission feature in the SEDs of type 1 AGN galaxies…

天体物理学 · 物理学 2009-11-10 C. P. Dullemond , I. M. van Bemmel

We fitted Spitzer/IRS ~2-35 um spectra of 26 luminous QSOs in attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow line region (NLR) clouds and a blackbody-like dust. The models…

宇宙学与河外天体物理 · 物理学 2011-02-11 Rivay Mor , Hagai Netzer , Moshe Elitzur

Tori of Active Galactic Nuclei are made up of a mixture of hot and cold gas, as well as dust. In order to protect the dust grains from destruction by the hot gas as well as by the energetic radiation of the accretion disk, the dust is often…

天体物理学 · 物理学 2009-11-13 M. Schartmann , K. Meisenheimer , M. Camenzind , S. Wolf , K. R. W. Tristram , Th. Henning

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

We discuss a clumpy model of obscuring dusty tori around AGN. Cloud-cloud collisions lead to an effective viscosity and a geometrically thick accretion disk, which has the required properties of a torus. Accretion in the combined…

天体物理学 · 物理学 2016-08-30 Thomas Beckert , Wolfgang J. Duschl , Bernd Vollmer

Deep surveys of {\em Chandra} and {\em HST} (Hubble Space Telescope) show that active galactic nucleus (AGN) populations are changing with hard X-ray luminosities. This arises an interesting question whether the dusty torus is evolving with…

天体物理学 · 物理学 2009-11-11 J. -M. Wang , E. P. Zhang , B. Luo

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 feedback by active galactic nuclei (AGNs) is significant for the formation and evolution of galaxies. It has been realized that the radiative pressure feedback could be an efficient mechanism due to the existence of dust. In this…

高能天体物理现象 · 物理学 2015-05-27 Yuan Liu , Shuang Nan Zhang

According to recent models, the accretion disk and black hole in active galactic nuclei are surrounded by a clumpy torus. We investigate the NIR flux variation of the torus in response to a UV flash for various geometries. Anisotropic…

宇宙学与河外天体物理 · 物理学 2015-05-28 Toshihiro Kawaguchi , Masao Mori

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central engine. The compact sizes (only a few pc) determined in recent high-resolution observations require that the obscuring matter be clumpy and…

天体物理学 · 物理学 2011-02-11 Moshe Elitzur , Isaac Shlosman

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

The dusty clumpy torus surrounds the central black hole (BH) and the accretion disk in active galactic nuclei, and governs the growth of super-massive BHs via gas fueling towards the central engine. Near-infrared (NIR) monitoring…

高能天体物理现象 · 物理学 2013-06-04 Toshihiro Kawaguchi

We revisit the dependence of covering factor (CF) of dust torus on physical properties of active galactic nuclei (AGNs) by taking into account an AGN polar dust emission. The CF is converted from a ratio of infrared (IR) luminosity…

We compare three different models of clumpy gas disk and show that the Circumnuclear Disk (CND) in the Galactic Center and a putative, geometrically thick, obscuring torus are best explained by a collisional model consisting of…

天体物理学 · 物理学 2009-11-10 B. Vollmer , T. Beckert , W. J. Duschl

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

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
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