Journal
ASTROPHYSICAL JOURNAL
Volume 749, Issue 1, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/749/1/32
Keywords
galaxies: active; galaxies: Seyfert; hydrodynamics; infrared: general; magnetohydrodynamics (MHD); quasars: general; radiative transfer
Categories
Funding
- National Sciences and Engineering Research Council of Canada
- Ontario Early Researcher Award Program
- Ontario Graduate Scholarship program
- NASA through Jet Propulsion Laboratory, California Institute of Technology
- NASA
- [NSF AST-0507367]
- [NSF AST-0907837]
- [NSF PHY-0215581]
- [NSF PHY-0821899]
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0907837] Funding Source: National Science Foundation
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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 torus is required in order to understand the fundamental physics of AGNs and interpret their observational signatures. Here, we explore self-similar, dusty disk winds, driven by both magnetocentrifugal forces and radiation pressure, as an explanation for the torus. Using these models, we make predictions of AGN infrared (IR) spectral energy distributions from 2 to 100 mu m by varying parameters such as the viewing angle (from i = 0 degrees to 90 degrees), the base column density of the wind (from N-H,(0) = 10(23) to 10(25) cm(-2)), the Eddington ratio (from L/L-Edd = 0.01 to 0.1), the black hole mass (from M-BH = 10(8) to 10(9) M-circle dot), and the amount of power in the input spectrum emitted in the X-ray relative to that emitted in the UV/optical (from alpha(ox) = 1.1 to 2.1). We find that models with N-H,N-0 = 10(25) cm(-2), L/L-Edd = 0.1, and M-BH >= 10(8) M-circle dot are able to adequately approximate the general shape and amount of power expected in the IR as observed in a composite of optically luminous Sloan Digital Sky Survey quasars. The effect of varying the relative power coming out in X-rays relative to the UV is a change in the emission below similar to 5 mu m from the hottest dust grains; this arises from the differing contributions to heating and acceleration of UV and X-ray photons. We see mass outflows ranging from similar to 1 to 4M(circle dot) yr(-1), terminal velocities ranging from similar to 1900 to 8000 km s(-1), and kinetic luminosities ranging from similar to 1 x 10(42) to 8 x 10(43) erg s(-1). Further development of this model holds promise for using specific features of observed IR spectra in AGNs to infer fundamental physical parameters of the systems.
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