Two Kerr black holes with axisymmetric spins: An improved Newtonian model for the head-on collision and gravitational radiation

TL;DR

This paper introduces an improved semi-analytical Newtonian model for head-on collisions of two Kerr black holes, accurately estimating gravitational radiation emission and exploring spin interactions.

Contribution

It provides a novel semi-analytical approach to model Kerr black hole collisions, including gravitational wave emission and spin-exchange effects.

Findings

Spin-spin interaction increases gravitational wave energy emission by up to 0.2%.

The model's predictions align with numerical investigations.

Discussion of spin-exchange mechanisms between black holes.

Abstract

We present a semi-analytical approach to the interaction of two (originally) Kerr black holes through a head-on collision process. An expression for the rate of emission of gravitational radiation is derived from an exact solution to the Einstein's field equations. The total amount of gravitational radiation emitted in the process is calculated and compared to current numerical investigations. We find that the spin-spin interaction increases the emission of gravitational wave energy up to 0.2% of the total rest mass. We discuss also the possibility of spin-exchange between the holes.