Gravity-dominated unequal-mass black hole collisions

TL;DR

This paper investigates high-energy collisions of unequal-mass black holes, finding that the energy radiated as gravitational waves is roughly 13% regardless of mass ratio, supporting the idea that object structure is irrelevant at high energies.

Contribution

It demonstrates that the gravitational wave energy emission in high-energy black hole collisions is independent of mass ratio, using perturbation theory and zero-frequency limit approximations.

Findings

Approximately 13% of energy radiated as gravitational waves at high energies.

Energy emission is independent of mass ratio in high-energy collisions.

Supports the conjecture that detailed structure of objects is irrelevant at high energies.

Abstract

We continue our series of studies of high-energy collisions of black holes investigating unequal-mass, boosted head-on collisions in four dimensions. We show that the fraction of the center-of-mass energy radiated as gravitational waves becomes independent of mass ratio and approximately equal to $13\%$ at large energies. We support this conclusion with calculations using black hole perturbation theory and Smarr's zero-frequency limit approximation. These results lend strong support to the conjecture that the detailed structure of the colliding objects is irrelevant at high energies.