共 3 条
Sub-parsec-scale dynamics of a dusty gas disc exposed to anisotropic AGN radiation with frequency-dependent radiative transfer
被引:51
|作者:
Namekata, Daisuke
[1
]
Umemura, Masayuki
[1
]
机构:
[1] Univ Tsukuba, Ctr Computat Sci, 1-1-1 Tennodai, Tsukuba, Ibaraki 3058577, Japan
关键词:
hydrodynamics;
radiative transfer;
methods: numerical;
ISM: jets and outflows;
galaxies: active;
ACTIVE GALACTIC NUCLEI;
BROAD-LINE REGION;
MULTIDIMENSIONAL COMPRESSIBLE FLOWS;
MONOTONIC NUMERICAL-METHODS;
SUPERMASSIVE BLACK-HOLES;
RAY PHOTOIONIZED MEDIA;
DOUBLY EXCITED-STATES;
FINITE-VOLUME METHOD;
HEAT-TRANSFER;
X-RAY;
D O I:
10.1093/mnras/stw862
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We explore the gas dynamics near the dust sublimation radius of active galactic nucleus (AGN). For the purpose, we perform axisymmetric radiation hydrodynamic simulations of a dusty gas disc of radius approximate to 1 pc around a supermassive black hole of mass 10(7) M-circle dot taking into account (1) anisotropic radiation of accretion disc, (2) X-ray heating by corona, (3) radiative transfer of infrared (IR) photons re-emitted by dust, (4) frequency dependence of direct and IR radiations, and (5) separate temperatures for gas and dust. As a result, we find that for Eddington ratio approximate to 0.77, a nearly neutral, dense (approximate to 10(6-8) cm(-3)), geometrically thin (h/r < 0.06) disc forms with a high-velocity (approximate to 200 similar to 3000 km s(-1)) dusty outflow launched from the disc surface. The disc temperature is determined by the balance between X-ray heating and various cooling, and the disc is almost supported by thermal pressure. Contrary to Krolik (2007), the radiation pressure by IR photons is not effective to thicken the disc, but rather compresses it. Thus, it seems difficult for a radiation-supported, geometrically thick, obscuring torus to form near the dust sublimation radius as far as the Eddington ratio is high (similar to 1). The mass outflow rate is 0.05-0.1 M-circle dot yr(-1) and the column density of the outflow is N-H similar to 10(21) cm(-2). To explain observed type-II AGN fraction, it is required that outflow gas is extended to larger radii (r greater than or similar to 10 pc) or that a denser dusty wind is launched from smaller radii (r similar to 10(4) R-g).
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页码:980 / 1018
页数:39
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