Radiation and outflow properties of super-Eddington accretion flows around various mass classes of black holes: Dependence on the accretion rates

Abstract

Abstract We perform axisymmetric two-dimensional radiation-hydrodynamic simulations of super-Eddington accretion flow and outflow around black holes to examine the properties of radiation and outflow as functions of the black hole mass and the accretion rate on to the black hole ($\dot{M}_{\rm BH}$). We find that the $\dot{m}_{\rm BH} ({\equiv} \dot{M}_{\rm BH}c^2 /L_{\rm Edd})$ dependence of $L_{\rm rad}/L_{\rm Edd}$ and $L_{\rm mech}/L_{\rm Edd}$ found for a stellar-mass black hole can apply to the high-mass cases, where $L_{\rm rad}$ is the radiation luminosity, $L_{\rm mech}$ is the mechanical luminosity, c is the speed of light, and $L_{\rm Edd}$ is the Eddington luminosity. Such universalities can appear in the regime in which electron scattering opacity dominates over absorption opacity. Further, the normalized isotropic mechanical luminosity $L_{\rm mech}^{\rm ISO}/L_{\rm Edd}$ (evaluated by normalized density and velocity at $\theta =10^\circ$) exhibits a broken power-law relationship with ${\dot{m}}_{\rm BH}$; $L_{\rm mech}^{\rm ISO}/ L_{\rm Edd} \propto {\dot{m}}_{\rm BH}^{2.7}$ (or $\propto {\dot{m}}_{\rm BH}^{0.7}$) below (above) ${\dot{m}}_{\rm BH}\sim 400$. This is because the radial velocity stays nearly constant (or even decreases) below (above) the break with increase of $\dot{m}_{\rm BH}$. We also find that the luminosity ratio is $L_{\rm mech}/L_{\rm rad}^{\rm ISO} \sim 0.05$ at ${\dot{m}}_{\rm BH} \sim 100$, which is roughly consistent with the observations of NLS1, 1H 0323+103.