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Related papers: Constraining AGN Torus Sizes with Optical and Mid-…

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The obscuration observed in active galactic nuclei (AGN) is mainly caused by dust and gas distributed in a torus-like structure surrounding the supermassive black hole (SMBH). However, properties of the obscuring torus of the AGN in X-ray…

Astrophysics of Galaxies · Physics 2021-06-09 X. Zhao , S. Marchesi , M. Ajello , D. Cole , Z. Hu , R. Silver , N. Torres-Albà

The time lag between optical and near-infrared (IR) flux variability can be taken as a means to determine the sublimation radius of the dusty "torus" around supermassive black holes in active galactic nuclei (AGN). I will show that data…

Astrophysics of Galaxies · Physics 2015-06-18 Sebastian F. Hoenig

We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy,…

The continued operation of the Wide-field Infrared Survey Explorer (WISE) combined with several ground-based optical transient surveys (e.g., CRTS, ASAS-SN and PTF) offer an unprecedented opportunity to explore the dust structures in…

Astrophysics of Galaxies · Physics 2019-11-19 Jianwei Lyu , George H. Rieke , Paul S. Smith

High spatial resolution mid-infrared (MIR) 12 \mum continuum imaging of low-luminosity active galactic nuclei (LLAGN) obtained by VLT/VISIR is presented. The goal of this investigation is to determine if the nuclear MIR emission of LLAGN is…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 D. Asmus , P. Gandhi , A. Smette , S. F. Hönig , W. J. Duschl

Spatially resolving the innermost torus in AGN is one of the main goals of its high-spatial-resolution studies. This could be done in the near-IR observations of Type 1 AGNs where we see directly the hottest dust grains in the torus. We…

Astrophysics · Physics 2009-11-13 Makoto Kishimoto , Sebastian F. Hoenig , Thomas Beckert , Gerd Weigelt

We propose a new method to explore the candidate super-Eddington active galactic nuclei (AGNs). We examine the properties of infrared (IR) emission from the inner edge of the dusty torus in AGNs, which are powered by super- or sub-Eddington…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Nozomu Kawakatu , Ken Ohsuga

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 S. F. Hoenig , M. Kishimoto

We present arcsecond-scale observations of the active galactic nuclei (AGNs) of seven nearby Seyfert galaxies observed from the Stratospheric Observatory For Infrared Astronomy (SOFIA) using the 31.5 and 37.1 um filters of the Faint Object…

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…

Recent infrared interferometric observations revealed sub-parsec scale dust distributions around active galactic nuclei (AGNs). Using images of CLUMPY torus models and NGC 1068 as an example, we demonstrate that the near- and mid-infrared…

Astrophysics of Galaxies · Physics 2021-12-22 R. Nikutta , E. Lopez-Rodriguez , K. Ichikawa , N. A. Levenson , C. Packham , S. F. Hönig , A. Alonso-Herrero

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,…

Astrophysics · Physics 2007-05-23 S. F. Hoenig , T. Beckert , K. Ohnaka , G. Weigelt

Estimating physical quantities such as the star formation rate, stellar mass and active galactic nucleus (AGN) fraction of galaxies is a key step in understanding galaxy formation and evolution. In order to estimate the uncertainties in the…

Astrophysics of Galaxies · Physics 2025-01-14 Michail Papadopoulos , Vicky Papadopoulou Lesta , Ioannis Michos , Duncan Farrah , Andreas Efstathiou

Optical observations cannot resolve the structure of active galactic nuclei (AGN), and a unified model for AGN was inferred mostly from indirect methods. Optical reverberation mapping allowed us to constrain the spatial dimension of the…

High Energy Astrophysical Phenomena · Physics 2017-12-05 P. A. Rojas Lobos , R. W. Goosmann , F. Marin , D. Savić

We present high-resolution Keck LWS SiC filter (10.5-12.9 micron) mid-IR (MIR) images and photometry of a sample of nearby LLAGN. All MIR images show extended emission on small scales (e.g. 90% maximum widths 18 - 106 pc) deep within the…

Astrophysics · Physics 2007-05-23 Bruce Grossan

We present the accretion disk size estimates for a sample of 19 active galactic nuclei (AGN) using the optical $g$, $r$, and $i$ band light curves obtained from the Zwicky Transient Facility (ZTF) survey. All the AGN have reliable…

Astrophysics of Galaxies · Physics 2022-01-14 Vivek Kumar Jha , Ravi Joshi , Hum Chand , Xue-Bing Wu , Luis C. Ho , Shantanu Rastogi , Qinchun Ma

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…

The ratio in number between unobscured (type 1) and obscured (type 2) AGNs is often used to explore the structure of the torus in the unified scheme for active galactic nuclei (AGNs). Oh et al. (2015) investigated the type 1 AGN fraction on…

Astrophysics of Galaxies · Physics 2017-09-20 Honggeun Khim , Sukyoung K. Yi

In the unified scheme of active galactic nuclei, a dusty torus absorbs and then reprocesses a fraction of the intrinsic luminosity which is emitted at longer wavelengths. Thus, subject to radiative transfer corrections, the fraction of the…

High Energy Astrophysical Phenomena · Physics 2017-11-08 Savithri H. Ezhikode , Poshak Gandhi , Chris Done , Martin Ward , Gulab C. Dewangan , Ranjeev Misra , Ninan Sajeeth Philip

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Toshihiro Kawaguchi , Masao Mori