Dynamical structure of magnetized dissipative accretion flow around black holes

TL;DR

This paper investigates the structure of magnetized, dissipative accretion flows around black holes, highlighting shock formation, flow dynamics, and energy dissipation, with implications for jets and observational signatures.

Contribution

It provides a comprehensive analysis of shock formation and flow structure in magnetized accretion disks, including the effects of viscosity, cooling, and magnetic fields, which was not extensively studied before.

Findings

Shock waves can form over a wide range of parameters.

Post-shock corona dynamics depend on flow parameters.

Energy dissipation at shocks can power jets and outflows.

Abstract

We study the global structure of optically thin, advection dominated, magnetized accretion flow around black holes. We consider the magnetic field to be turbulent in nature and dominated by the toroidal component. With this, we obtain the complete set of accretion solutions for dissipative flows where bremsstrahlung process is regarded as the dominant cooling mechanism. We show that rotating magnetized accretion flow experiences virtual barrier around black hole due to centrifugal repulsion that can trigger the discontinuous transition of the flow variables in the form of shock waves. We examine the properties of the shock waves and find that the dynamics of the post-shock corona (PSC) is controlled by the flow parameters, namely viscosity, cooling rate and strength of the magnetic field, respectively. We separate the effective region of the parameter space for standing shock and observe that shock can form for wide range of flow parameters. We obtain the critical viscosity parameter that allows global accretion solutions including shocks. We estimate the energy dissipation at the PSC from where a part of the accreting matter can deflect as outflows and jets. We compare the maximum energy that could be extracted from the PSC and the observed radio luminosity values for several super-massive black hole sources and the observational implications of our present analysis are discussed.