Simulation of microquasars -- the challenge of scales

TL;DR

This paper reports on multi-scale, multi-physics 3D hydrodynamical simulations of wind accretion in microquasars, revealing the critical role of shocks in structure formation and disk characteristics near black holes.

Contribution

It introduces a novel multi-scale simulation approach for microquasars and presents initial findings on accretion disk formation and shock influence.

Findings

Accretion disks are formed but are far from Keplerian.

Shocks are crucial for structure formation across all scales.

Turbulent fluctuations are generated by shocks.

Abstract

We present first results of a long-term project which aims at multi-scale, multi-physics simulations of wind accretion in microquasars and high-mass X-ray binaries. The 3D hydrodynamical simulations cover all scales, from the circum-binary environment down to the immediate vicinity of the black hole. We first introduce the numerical method and parallelization strategy of the AMR A-MAZE code. We then discuss some preliminary results of how, and on what scales, an accretion disk is formed around the black hole. We finally present some characteristics of this disk, which is far from Keplerian. We emphasize that on all scales shocks play a decisive role for the accretion process and the process of structure formation -- for the formation of the large scale, nearly coherent structure of the disk, but also for the formation of turbulent fluctuations.