Blandford-Znajek mechanism in black holes in alternative theories of gravity

TL;DR

This paper explores how deviations from the Kerr metric in alternative gravity theories affect the Blandford-Znajek mechanism for black hole jet formation, proposing a potential method to test black hole nature.

Contribution

It analyzes the impact of non-Kerr metrics on the Blandford-Znajek process and discusses how jet power measurements could test deviations from general relativity.

Findings

Deviations from Kerr metric alter jet power estimates.

Current measurement precision limits testing of alternative theories.

Future precise measurements could make this method competitive.

Abstract

According to the Blandford-Znajek mechanism, black hole jets are powered by the rotational energy of the compact object. In this work, we consider the possibility that the metric around black holes may not be described by the Kerr solution and we study how this changes the Blandford-Znajek model. If the Blandford-Znajek mechanism is responsible for the formation of jets, the estimate of the jet power in combination with another measurement can test the nature of black hole candidates and constrain possible deviations from the Kerr solution. However, this approach might become competitive with respect to other techniques only when it will be possible to have measurements much more precise than those available today.