Numerical Simulation of Hot Accretion Flow around Bondi Radius

TL;DR

This paper investigates the presence of winds in hot accretion flows around the Bondi radius through hydrodynamical simulations, revealing that winds can form when nuclear star gravity is weak, affecting mass inflow rates.

Contribution

It demonstrates that winds can be produced around the Bondi radius in the absence of nuclear star gravity, expanding understanding of accretion flow dynamics at large scales.

Findings

Winds are present around Bondi radius without nuclear star gravity.

Mass inflow rate decreases inward due to wind-driven mass loss.

Thermal conduction's role in wind formation is analyzed.

Abstract

Previous numerical simulations have shown that strong winds can be produced in the hot accretion flows around black holes. Most of those studies focus only on the region close to the central black hole, therefore it is unclear whether the wind production stops at large radii around Bondi radius. Bu et al. 2016 studied the hot accretion flow around the Bondi radius in the presence of nuclear star gravity. They find that when the nuclear stars gravity is important/comparable to the black hole gravity, winds can not be produced around the Bondi radius. However, for some galaxies, the nuclear stars gravity around Bondi radius may not be strong. In this case, whether winds can be produced around Bondi radius is not clear. We study the hot accretion flow around Bondi radius with and without thermal conduction by performing hydrodynamical simulations. We use the virtual particles trajectory method to study whether winds exist based on the simulation data. Our numerical results show that in the absence of nuclear stars gravity, winds can be produced around Bondi radius, which causes the mass inflow rate decreasing inwards. We confirm the results of Yuan et al. which indicates this is due to the mass loss of gas via wind rather convectional motions.