Estimation of mass outflow rates from viscous relativistic accretion discs around black holes

TL;DR

This paper models viscous relativistic accretion disks around non-rotating black holes, analyzing shock formation, jet launching, and outflow rates within a full general relativistic framework.

Contribution

It provides a comprehensive general relativistic analysis of accretion-ejection solutions, including shock dynamics and mass outflow rates, extending previous Newtonian or simplified models.

Findings

Steady shocks cannot exist for viscosity parameter $eta extgreater 0.06$ in GR.

Mass outflow rate peaks at an intermediate shock location.

Maximum jet terminal speed exceeds 0.1c for shocks within 20 gravitational radii.

Abstract

We investigated flow in Schwarzschild metric, around a non-rotating black hole and obtained self-consistent accretion - ejection solution in full general relativity. We covered the whole of parameter space in the advective regime to obtain shocked, as well as, shock-free accretion solution. We computed the jet streamline using von - Zeipel surfaces and projected the jet equations of motion on to the streamline and solved them simultaneously with the accretion disc equations of motion. We found that steady shock cannot exist {for $\alpha \gsim0.06$} in the general relativistic prescription, but is lower if mass - loss is considered too. We showed that for fixed outer boundary, the shock moves closer to the horizon with increasing viscosity parameter. The mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock {location}. The jet terminal speed increases with stronger shocks, quantitatively speaking, the terminal speed of jets $v_{{\rm j}\infty} > 0.1$ if $\rsh < 20 \rg$. The maximum of the outflow rate obtained in the general relativistic regime is less than $6\%$ of the mass accretion rate.