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相关论文: The central parsecs of active galactic nuclei: cha…

200 篇论文

In this paper we study the nuclear obscuration of galaxies hosting LINERs based on their X-ray and optical emission. They show column densities (N_H) at soft energies (0.5-2 keV) mostly related to the diffuse emission around the AGN,…

星系天体物理 · 物理学 2014-11-20 O. Gonzalez-Martin , J. Masegosa , I. Marquez , M. Guainazzi

First results from the AGN-Heidelberg program aimed at spatially resolving the central pc region of the closest Active Galactic Nuclei are presented. The core region of prototype active nuclei are clearly unveiled at IR waves and at…

天体物理学 · 物理学 2009-11-10 M. Almudena Prieto , Klaus Meisenheimer

Type 2 active galactic nuclei (AGN) show signatures of accretion onto a supermassive black hole through strong, high-ionization, narrow emission lines extended on scales of 100s to 1000s of parsecs, but they lack the broad emission lines…

高能天体物理现象 · 物理学 2022-09-21 M. Lynne Saade , Murray Brightman , Daniel Stern , Matthew A. Malkan , Javier A. Garcia

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 presence of the dust in the circumnuclear region strongly affects our view of the nucleus itself. The effect is strong in type 2 objects but weaker effect is likely to be present in type 1 objects as well. In these objects a correction…

天体物理学 · 物理学 2007-05-23 B. Czerny

The unification theory of active galactic nuclei (AGNs) hypothesizes that all AGNs are surrounded by an anisotropic dust torus and are essentially the same objects but viewed from different angles. However, little is known about the dust…

星系天体物理 · 物理学 2017-01-18 Yanxia Xie , Aigen Li , Lei Hao

The "torus" obscurer of Active Galactic Nuclei (AGN) is poorly understood in terms of its density, substructure and physical mechanisms. Large X-ray surveys provide model boundary constraints, for both Compton-thin and Compton-thick levels…

高能天体物理现象 · 物理学 2017-01-11 Johannes Buchner , Franz E. Bauer

We present polarimetric maps of the Circinus galaxy nucleus in the $BVRI$ bands, obtained with VLT/FORS2. Circinus is the closest Seyfert 2 galaxy and harbours an archetypal obscured active galactic nucleus (AGN). Recent high angular…

We present observational evidences that dust in the circumnuclear region of AGNs has different properties than in the Galactic diffuse interstellar medium. By comparing the reddening of optical and infrared broad lines and the X-ray…

天体物理学 · 物理学 2009-10-31 R. Maiolino , A. Marconi , M. Salvati , G. Risaliti , P. Severgnini , F. La Franca , L. Vanzi

We combine two approaches to isolate the AGN luminosity at near-infrared wavelengths and relate the near-IR pure AGN luminosity to other tracers of the AGN. Using integral-field spectroscopic data of an archival sample of 51 local AGNs, we…

We explore a detailed model in which the active galactic nucleus (AGN) obscuration results from the extinction of AGN radiation in a global flow driven by the pressure of infrared radiation on dust grains. We assume that external…

高能天体物理现象 · 物理学 2012-03-15 A. Dorodnitsyn , T. Kallman , G. S. Bisnovatyi-Kogan

The role of star-formation driven outflows in the obscuration of the central source in the Active Galactic Nuclei (AGN) is discussed. The outflow from a sub-parsec scale accretion disc is numerically modelled for parameters appropriate to…

天体物理学 · 物理学 2008-11-26 Sergei Nayakshin , Jorge Cuadra

The advent of high-angular resolution IR and sub-mm interferometry allows for spatially-resolved observations of the parsec-scale environment of active galactic nuclei (AGN), commonly referred to as the "torus." While molecular lines show…

星系天体物理 · 物理学 2019-11-06 Sebastian F. Hönig

We present a large sample of infrared-luminous candidate active galactic nuclei (AGNs) that lack X-ray detections in Chandra, XMM-Newton, and NuSTAR fields. We selected all optically detected SDSS sources with redshift measurements,…

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

(abridged) It is generally assumed that the distribution of dust on parsec scales forms a geometrically- and optically-thick entity in the equatorial plane around the accretion disk and broad-line region - dubbed "dust torus" - that emits…

How do active galactic nuclei with low optical luminosities produce powerful radio emission? Recent studies of active galactic nuclei with moderate radio and low optical luminosities (Fanaroff & Riley class I, FR I) searching for broad…

星系天体物理 · 物理学 2021-01-19 R. C. Gleisinger , C. P. O'Dea , J. F. Gallimore , S. Wykes , S. A. Baum

Highly obscured active galactic nuclei (AGN) are common in nearby galaxies, but are difficult to observe beyond the local Universe, where they are expected to significantly contribute to the black hole accretion rate density. Furthermore,…

Active galactic nuclei (AGN) are generally accepted to be powered by the release of gravitational energy in a compact accretion disk surrounding a massive black hole. Such disks are also necessary to collimate powerful radio jets seen in…

天体物理学 · 物理学 2009-10-30 Jack F. Gallimore , Stefi A. Baum , Christopher P. O'Dea

Obscured AGN represent a significant fraction of the entire AGN population, especially at high redshift (~70% at z=3--5). They are often characterized by the presence of large gas and dust reservoirs that are thought to sustain and possibly…