Head--on Collision of Two Unequal Mass Black Holes

TL;DR

This paper reports the first fully nonlinear numerical simulations of head-on collisions between unequal mass black holes, analyzing gravitational waveforms, energy radiation, and recoil velocities across various parameters.

Contribution

It provides new fully nonlinear simulation data for unequal mass black hole collisions, validating perturbation studies and assessing recoil effects.

Findings

Waveforms of dominant quasinormal modes are characterized.

Total radiated energies are quantified.

Recoil velocities are found to be astrophysically insignificant.

Abstract

We present results from the first fully nonlinear numerical calculations of the head--on collision of two unequal mass black holes. Selected waveforms of the most dominant l=2, 3 and 4 quasinormal modes are shown, as are the total radiated energies and recoil velocities for a range of mass ratios and initial separations. Our results validate the close and distant separation limit perturbation studies, and suggest that the head--on collision scenario is not likely to produce an astrophysically significant recoil effect.