Energy, momentum and mass outflows and feedback from thick accretion discs around rotating black holes

TL;DR

This study uses advanced simulations to analyze energy, momentum, and mass outflows from thick accretion discs around rotating black holes, revealing distinct jet and wind modes with implications for galaxy feedback.

Contribution

It provides new empirical formulas for outflow rates and clarifies how black hole spin and magnetic flux influence jet and wind power in accretion systems.

Findings

Jet power strongly depends on black hole spin and magnetic flux.

Jets dominate energy output unless spin or flux are very small.

Winds, though less powerful, can significantly affect their host galaxy.

Abstract

Using long-duration general relativistic magnetohydrodynamic simulations of radiatively inefficient accretion discs, the energy, momentum and mass outflow rates from such systems are estimated. Outflows occur via two fairly distinct modes: a relativistic jet and a sub-relativistic wind. The jet power depends strongly on the black hole spin and on the magnetic flux at the horizon. Unless these are very small, the energy output in the jet dominates over that in the wind. For a rapidly spinning black hole accreting in the magnetically arrested limit, it is confirmed that jet power exceeds the total rate of accretion of rest mass energy. However, because of strong collimation, the jet probably does not have a significant feedback effect on its immediate surroundings. The power in the wind is more modest and shows a weaker dependence on black hole spin and magnetic flux. Nevertheless, because the wind subtends a large solid angle, it is expected to provide efficient feedback on a wide range of scales inside the host galaxy. Empirical formulae are obtained for the energy and momentum outflow rates in the jet and the wind.