Applying black hole perturbation theory to numerically generated spacetimes

TL;DR

This paper discusses a practical method for applying black hole perturbation theory to numerically generated spacetimes, enabling the analysis of nonspherical perturbations in complex numerical relativity simulations.

Contribution

It provides a detailed procedure and theoretical discussion for extracting nonspherical perturbations from numerical relativity initial data.

Findings

Method successfully extracts perturbations from numerical data

Enables analysis of gravitational radiation in nonlinear simulations

Bridges numerical relativity with perturbation theory

Abstract

Nonspherical perturbation theory has been necessary to understand the meaning of radiation in spacetimes generated through fully nonlinear numerical relativity. Recently, perturbation techniques have been found to be successful for the time evolution of initial data found by nonlinear methods. Anticipating that such an approach will prove useful in a variety of problems, we give here both the practical steps, and a discussion of the underlying theory, for taking numerically generated data on an initial hypersurface as initial value data and extracting data that can be considered to be nonspherical perturbations.