Three-dimensional structure of clumpy outflow from supercritical accretion flow onto black holes
Feb 2, 201812 pages
Published in:
- Publ.Astron.Soc.Jap. 70 (2018) 2, 22
- Published: Mar 1, 2018
e-Print:
- 1802.00567 [astro-ph.HE]
DOI:
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Abstract: (Oxford University Press)
We perform global three-dimensional (3D) radiation-hydrodynamic (RHD) simulations of outflow from supercritical accretion flow around a 10 M_⊙ black hole. We only solve the outflow part, starting from the axisymmetric 2D simulation data in a nearly steady state but with small perturbations in a sinusoidal form being added in the azimuthal direction. The mass accretion rate onto the black hole is ∼10^2L_E/c^2 in the underlying 2D simulation data, and the outflow rate is ∼10 L_E/c^2 (with L_E and c being the Eddington luminosity and speed of light, respectively). We first confirm the emergence of clumpy outflow, which was discovered by the 2D RHD simulations, above the photosphere located at a few hundreds of Schwarzschild radii (r_S) from the central black hole. As prominent 3D features we find that the clumps have the shape of a torn sheet, rather than a cut string, and that they are rotating around the central black hole with a sub-Keplerian velocity at a distance of ∼10^3 r_S from the center. The typical clump size is ∼30 r_S or less in the radial direction, and is more elongated in the angular directions, ∼ hundreds of r_S at most. The sheet separation ranges from 50 to 150 r_S. We expect stochastic time variations when clumps pass across the line of the sight of a distant observer. Variation timescales are estimated to be several seconds for a black hole with mass of ten to several tens of M_⊙, in rough agreement with the observations of some ultra-luminous X-ray sources.Note:
- 12 pages, 8 figures, accepted for publication in PASJ
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