Slowly Rotating Accretion Flow Around Supermassive Black Holes in Elliptical Galaxies: Case With Outflow

Abstract

Observational evidence and many numerical simulations show the existence of winds (i.e., uncollimated outflows) in the accretion systems of elliptical galaxy centers. One of the primary aims of this study is to investigate the solutions of slowly rotating accretion flows around supermassive black holes with outflows. This paper presents two distinct physical regions, supersonic and subsonic, which extend from the outer boundary to the black hole. In our numerical solution, the outer boundary is chosen beyond the Bondi radius. Due to strong gravity, we ignore outflow (i.e., s = 0) in the inner region (within ∼10 r _s ). The radial velocity of the flow at the outer region is significantly increased due to the presence of the outflow. Compared to previous works, the accretion mode, namely, the slowly rotating case, that corresponds to low accretion rates that have general wind output is carefully described, and the effect of the galaxy potential and feedback by the wind in this mode are taken into account. As the power-law form of the mass accretion rate is mathematically compatible with our equations, we consider a radius-dependent mass accretion rate ( ${\dot{M}}_{\mathrm{in}}\propto {r}^{s}$ ), where s is a free parameter and shows the intensity of outflow. There is an unknown mechanism for removing the mass, angular momentum, and energy by outflows in this study. The effects of the outflow appear well on the outer edge of the flow.

Keywords

• Elliptical galaxies
• Accretion