ACTIVE GALACTIC NUCLEUS OBSCURATION THROUGH DUSTY INFRARED-DOMINATED FLOWS. I. RADIATION-HYDRODYNAMICS SOLUTION FOR THE WIND

Journal Article · Tue Nov 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/741/1/29; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587304

Dorodnitsyn, A; Kallman, T ^[1]; Bisnovatyi-Kogan, G S ^[2]

---

1. Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
2. Space Research Institute, 84/32, Profsoyuznaya st., Moscow (Russian Federation)

We construct a radiation-hydrodynamics model for the obscuring toroidal structure in active galactic nuclei. In this model the obscuration is produced at parsec scales by a dense, dusty wind which is supported by infrared radiation pressure on dust grains. To find the distribution of radiation pressure, we numerically solve the two-dimensional radiation transfer problem in a flux-limited diffusion approximation. We iteratively couple the solution with calculations of stationary one-dimensional models for the wind and obtain the z-component of the velocity. Our results demonstrate that for active galactic nucleus (AGN) luminosities greater than 0.1 L{sub edd}, external illumination can support a geometrically thick obscuration via outflows driven by infrared radiation pressure. The terminal velocity of marginally Compton-thin models (0.2 < {tau}{sub T} < 0.6) is comparable to or greater than the escape velocity. In Compton-thick models the maximum value of the vertical component of the velocity is lower than the escape velocity, suggesting that a significant part of our torus is in the form of failed wind. The results demonstrate that obscuration via normal or failed infrared-driven winds is a viable option for the AGN torus problem and AGN unification models. Such winds can also provide an important channel for AGN feedback.

• OSTI ID: 21587304
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 741; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DUSTS
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
GALAXIES
GALAXY NUCLEI
HYDRODYNAMICS
INFRARED RADIATION
LUMINOSITY
MECHANICS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION PRESSURE
RADIATIONS
STELLAR ACTIVITY
STELLAR WINDS
VELOCITY