Shocks in the relativistic transonic accretion with low angular momentum

TL;DR

This paper investigates relativistic accretion flows with low angular momentum through simulations, revealing shock formation, oscillations, and potential links to observed quasi-periodic oscillations in black hole systems.

Contribution

It introduces a comprehensive simulation study of low angular momentum accretion flows, exploring shock dynamics and oscillations across different black hole parameters.

Findings

Shock formation occurs in certain parameter regimes.

Oscillating shocks can cause flaring in accretion rates.

Results are scalable to different black hole masses and comparable to observed QPOs.

Abstract

We perform 1D/2D/3D relativistic hydrodynamical simulations of accretion flows with low angular momentum, filling the gap between spherically symmetric Bondi accretion and disc-like accretion flows. Scenarios with different directional distributions of angular momentum of falling matter and varying values of key parameters such as spin of central black hole, energy and angular momentum of matter are considered. In some of the scenarios the shock front is formed. We identify ranges of parameters for which the shock after formation moves towards or outwards the central black hole or the long lasting oscillating shock is observed. The frequencies of oscillations of shock positions which can cause flaring in mass accretion rate are extracted. The results are scalable with mass of central black hole and can be compared to the quasi-periodic oscillations of selected microquasars (such as GRS 1915+105, XTE J1550-564 or IGR J17091-3624), as well as to the supermassive black holes in the centres of weakly active galaxies, such as Sgr $A^{*}$.