ACTIVE GALACTIC NUCLEUS OBSCURATION THROUGH DUSTY INFRARED-DOMINATED FLOWS. I. RADIATION-HYDRODYNAMICS SOLUTION FOR THE WIND
- Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
- 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, Vol. 741, Issue 1; Other Information: DOI: 10.1088/0004-637X/741/1/29; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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