Slowly Rotating Accretion Flow Around SMBH in Elliptical Galaxy: Case With Outflow

TL;DR

This study investigates slowly rotating accretion flows with outflows around SMBHs in elliptical galaxies, highlighting the impact of winds on flow dynamics and the importance of galaxy potential and feedback effects.

Contribution

It introduces a detailed numerical model of accretion flows with outflows, considering a radius-dependent accretion rate and feedback effects, extending previous work on low accretion rate regimes.

Findings

Outflows significantly increase radial velocity at outer regions.

The accretion mode with outflows is characterized by a power-law mass accretion rate.

Galaxy potential and wind feedback influence flow structure and dynamics.

Abstract

Observational evidence and many numerical simulations show the existence of wind (i.e., uncollimated outflow) in accretion systems of the elliptical galaxy center. One of the primary aims of this study is to investigate the solutions of slowly rotating accretion flows around the supermassive black hole with outflow. This paper presents two distinct physical regions: supersonic and subsonic, that 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 $\sim 10 r_s$). 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 one accretion mode - namely, slowly rotating case, which corresponds to low accretion rates that have general wind output is carefully described, and the effect of galaxy potential and the feedback effects by the wind in this mode are taken into account. Since the power-law form of the mass accretion rate is mathematically compatible with our equations, we consider a radius-dependent mass accretion rate ($\dot{M}_{in} \propto r^s$), 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.