Radiation content of Conformally flat initial data

TL;DR

This paper investigates the gravitational radiation emitted during head-on collisions of binary black holes from rest, analyzing how initial data choices influence the emitted energy and momentum in the extreme mass ratio limit.

Contribution

It identifies the radiation contributions from conformally flat initial data and assesses their impact on the emitted energy and momentum in black hole collisions.

Findings

Radiation is not dominated by initial data details for initial separations ≥7M.

Conformally flat initial data may better approximate radiation in non-headon orbits.

Initial data choice influences the amount of emitted gravitational radiation.

Abstract

We study the radiation of energy and linear momentum emitted to infinity by the headon collision of binary black holes, starting from rest at a finite initial separation, in the extreme mass ratio limit. For these configurations we identify the radiation produced by the initially conformally flat choice of the three geometry. This identification suggests that the radiated energy and momentum of headon collisions will not be dominated by the details of the initial data for evolution of holes from initial proper separations $L_0\geq7M$. For non-headon orbits, where the amount of radiation is orders of magnitude larger, the conformally flat initial data may provide a relative even better approximation.