Slicing the Torus: Obscuring Structures in Quasars

Abstract

Quasars and Active Galactic Nuclei (AGNs) are often obscured by dust and gas. It is normally assumed that the obscuration occurs in an oblate "obscuring torus", that begins at the radius at which the most refractive dust can remain solid. The most famous form of this torus is a donut-shaped region of molecular gas with a large scale-height. While this model is elegant and accounts for many phenomena at once, it does not hold up to detailed tests. Instead the obscuration in AGNs must occur on a wide range of scales and be due to a minimum of three physically distinct absorbers. Slicing the "torus" into these three regions will allow interesting physics of the AGN to be extracted.

8 pages, 1 figure. To appear in the proceedings of the conference "The central kiloparsec in Galactic Nuclei:Astronomy at High Angular Resolution 2011", open access Journal of Physics: Conference Series (JPCS), published by IOP Publishing

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Cited by in corpus (12)

• Revisiting the Unified Model of Active Galactic Nuclei
• First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN
• Dust Attenuation in High Redshift Galaxies -- 'Diamonds in the Sky'
• The Chandra COSMOS Legacy Survey: Compton Thick AGN at high redshift
• Obscuring Fraction of Active Galactic Nuclei: Implications from Radiation-driven Fountain Models
• IR-derived covering factors for a large sample of quasars from WISE-UKIDSS-SDSS
• A New Compton-thick AGN in our Cosmic Backyard: Unveiling the Buried Nucleus in NGC 1448 with NuSTAR
• X-ray spectroscopy of the z=6.4 quasar J1148+5251
• Simultaneous XMM-\textit{Newton} and HST-COS observation of 1H0419-577: II. Broadband spectral modeling of a variable Seyfert galaxy
• Obscured flat spectrum radio AGN as sources of high-energy neutrinos
• Toroidal figures of equilibrium from a 2nd-order accurate, accelerated SCF-method with subgrid approach
• The role of molecular gas in the nuclear regions of IRAS 00183-7111. ALMA and X-ray investigations of an ultraluminous infrared galaxy