Large-scale outflow structure and radiation properties of super-Eddington flow: Dependence on the accretion rates

Abstract

In order to precisely evaluate the impacts by super-Eddington accretors to their environments, it is essential to assure a large enough simulation box and long computational time to avoid any artefacts from numerical settings as much as possible. In this paper, we carry out axisymmetric two-dimensional radiation hydrodynamic simulations around a $10M_{\odot }$ black hole in large simulation boxes and study the large-scale outflow structure and radiation properties of super-Eddington accretion flow for a variety of black hole accretion rates, ${\dot{M}}_{\mathrm{BH}}=(110-380)L_{\mathrm{Edd}}/c^2$. The Keplerian radius of the inflow material, at which centrifugal force balances with gravitational force, is fixed to 2430 Schwarzschild radii.We find that the mechanical luminosity grows more rapidly than the radiation luminosity with an increase of ${\dot{M}}_{\mathrm{BH}}$. When seen from a nearly face-on direction, especially, the isotropic mechanical luminosity grows in proportion to ${\dot{M}}_{\mathrm{BH}}^{2.7}$, while the total mechanical luminosity is proportional to ${\dot{M}}_{\mathrm{BH}}^{1.7}$. The reason for the former is that the higher ${\dot{M}}_{\mathrm{BH}}$ is, the more vertically inflated becomes the disk surface, which makes radiation fields more confined in the region around the rotation axis, thereby strongly accelerating outflowing gas. The outflow is classified into pure outflow and failed outflow, depending whether outflowing gas can reach the outer boundary of the simulation box or not. The fraction of the failed outflow decreases with a decrease of ${\dot{M}}_{\mathrm{BH}}$. We analyze physical quantities along each outflow trajectory, finding that the Bernoulli parameter ($Be$) is not a good indicator to discriminate pure and failed outflows, since it is never constant because of continuous acceleration by radiation-pressure force.Pure outflow can arise, even if $Be<0$ at the launching point.

18 pages, 13 figures, 3 tables, accepted for publication in PASJ

References in corpus (18)

• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• Super-critically accreting stellar-mass black holes as ultraluminous X-ray sources
• An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
• A Global Three Dimensional Radiation Magneto-hydrodynamic Simulation of Super-Eddington Accretion Disks
• Discovery of coherent pulsations from the Ultraluminous X-ray Source NGC 7793 P13
• A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source
• Global simulations of axisymmetric radiative black hole accretion disks in general relativity with a sub-grid magnetic dynamo
• A spectral-timing model for ULXs in the super-critical regime
• Numerical Simulations of Optically Thick Accretion onto a Black Hole - II. Rotating Flow
• Puffy accretion disks: sub-Eddington, optically thick, and stable
• Bridging the gap between stellar-mass black holes and ultraluminous X-ray sources
• On the radiation beaming of bright X-ray pulsars and constraints on neutron star mass-radius relation
• A radiation-hydrodynamic model of accretion columns for ultra-luminous X-ray pulsars
• Radiation hydrodynamics simulations of wide-angle outflows from super-critical accretion disks around black holes
• Theoretical modeling of Comptonized X-ray spectra of super-Eddington accretion flow: origin of hard excess in Ultraluminous X-Ray Sources
• Optical Spectroscopy of the environment of a ULX in NGC 7331
• Component of energy flow from supercritical accretion disks around rotating stellar mass black holes
• Structure of the super-Eddington outflow and itsimpact on the cosmological scale

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