Retarded radiation from colliding black holes in the close limit

TL;DR

This paper introduces a new null hypersurface technique to calculate gravitational waveforms from colliding black holes, revealing features that could improve gravitational wave detection methods.

Contribution

It presents a novel approach using null hypersurfaces to compute waveforms in black hole mergers, highlighting features that enhance signal extraction.

Findings

Waveform exhibits initial quasinormal ringup.

Weak dependence on collision velocity parameter.

Potential for improved gravitational wave templates.

Abstract

We use null hypersurface techniques in a new approach to calculate the retarded waveform from a binary black hole merger in the close approximation. The process of removing ingoing radiation from the system leads to two notable features in the shape of the close approximation waveform for a head-on collision of black holes: (i) an initial quasinormal ringup and (ii) weak sensitivity to the parameter controlling the collision velocity. Feature (ii) is unexpected and has the potential importance of enabling the design of an efficient template for extracting the gravitational wave signal from the noise.