Unambiguous determination of gravitational waveforms from binary black hole mergers

TL;DR

This paper presents a method to accurately determine gravitational waveforms at null infinity from binary black hole mergers, providing the first unambiguous waveforms for such events.

Contribution

It introduces a general-purpose characteristic extraction technique to compute gravitational radiation at null infinity from finite-radius data.

Findings

First unambiguous merger waveforms at null infinity

Method applicable to data from different computational approaches

Improves accuracy of gravitational wave measurements

Abstract

Gravitational radiation is properly defined only at future null infinity ($\scri$), but in practice it is estimated from data calculated at a finite radius. We have used characteristic extraction to calculate gravitational radiation at $\scri$ for the inspiral and merger of two equal mass non-spinning black holes. Thus we have determined the first unambiguous merger waveforms for this problem. The implementation is general purpose, and can be applied to calculate the gravitational radiation, at $\scri$, given data at a finite radius calculated in another computation.