The Evolution of Distorted Rotating Black Holes II: Dynamics and Analysis

TL;DR

This paper presents a numerical study of distorted, rotating black holes, analyzing their evolution, gravitational waveforms, and horizon properties, with high rotation parameters up to 0.87, providing insights into their dynamics and energy emission.

Contribution

Developed a numerical code to evolve distorted Kerr and Schwarzschild black holes with high rotation, analyzing gravitational waves and horizon dynamics.

Findings

Excited quasinormal modes in all cases

Black hole masses from apparent horizons match ADM mass

Extracted gravitational waveforms for various rotation parameters

Abstract

We have developed a numerical code to study the evolution of distorted, rotating black holes. This code is used to evolve a new family of black hole initial data sets corresponding to distorted ``Kerr'' holes with a wide range of rotation parameters, and distorted Schwarzschild black holes with odd-parity radiation. Rotating black holes with rotation parameters as high as $a/m=0.87$ are evolved and analyzed in this paper. The evolutions are generally carried out to about $t=100M$, where $M$ is the ADM mass. We have extracted both the even- and odd-parity gravitational waveforms, and find the quasinormal modes of the holes to be excited in all cases. We also track the apparent horizons of the black holes, and find them to be a useful tool for interpreting the numerical results. We are able to compute the masses of the black holes from the measurements of their apparent horizons, as well as the total energy radiated and find their sum to be in excellent agreement with the ADM mass.