Radiation hydrodynamics simulations of wide-angle outflows from super-critical accretion disks around black holes

Abstract

By performing two-dimensional radiation hydrodynamics simulations with large computational domain of 5000 Schwarzschild radius, we revealed that wide-angle outflow is launched via the radiation force from the super-critical accretion flows around black holes. The angular size of the outflow, of which the radial velocity (v_r) is over the escape velocity (v_esc), increases with an increase of the distance from the black hole. As a result, the mass is blown away with speed of v_r > v_esc in all direction except for the very vicinity of the equatorial plane, theta=0-85^circ, where theta is the polar angle. The mass ejected from the outer boundary per unit time by the outflow is larger than the mass accretion rate onto the black hole, ~150L_Edd/c^2, where L_Edd and c are the Eddington luminosity and the speed of light. Kinetic power of such wide-angle high-velocity outflow is comparable to the photon luminosity and is a few times larger than the Eddington luminosity. This corresponds to ~10^39-10^40 erg/s for the stellar mass black holes. Our model consistent with the observations of shock excited bubbles observed in some ultra-luminous X-ray sources (ULXs), supporting a hypothesis that ULXs are powered by the super-critical accretion onto stellar mass black holes.