On the dynamics of the torus around the kicked black hole

TL;DR

This paper investigates how a kicked black hole influences the dynamics of a surrounding accretion torus, revealing spiral wave and shock formations that affect accretion processes, using general relativistic hydrodynamical simulations.

Contribution

It introduces a detailed simulation study of the effects of black hole kicks on accretion tori, highlighting the excitation of spiral waves and shocks that impact accretion dynamics.

Findings

Spiral wave structures are excited on the torus due to black hole kicks.

Higher kick velocities prolong the time to reach saturation.

Spiral shocks facilitate angular momentum loss and matter accretion.

Abstract

There is a special interest to understand the dynamical properties of the accretion disk created around the newly formed black hole due to the supermassive black hole binaries which merge inside the gaseous disk. The newly formed black hole would have a kick velocity at up to thousands of km/s that drives a perturbation on a newly accreted torus around the black hole. Some of the observed supermassive black holes at the center of the Active Galactic Nucleus (AGN) move with a certain velocity relative to its broader accretion disk. In this paper, the effects of the kicked black holes onto the infinitesimally thin accreted torus are studied by using the general relativistic hydrodynamical code, focusing on changing the dynamics of the accretion disk during the accretion disk-black hole interaction. We have found the non-axisymmetric global mode m=1 inhomogeneity, which causes a spiral-wave structure, is excited on the torus due to kicked black hole. The higher the perturbation velocity produced by the kicked black hole, the longer time the torus takes to reach the saturation point. The created spiral density waves which rapidly evolve into the spiral shocks are also observed from the numerical simulations. The spiral shock is responsible for accreting matter toward the black hole. Firstly, the spiral-wave structure is developed and the accretion through the spiral arms is stopped around the black hole. At the later time of simulation, the formed spiral shocks partly cause the angular momentum loss across the torus.