Wave and Particle Scattering Properties of High Speed Black Holes

TL;DR

This paper investigates the scattering properties of high-speed black holes, revealing how particles and electromagnetic waves interact with the impulsive gravitational wave generated in the light-like limit of Kerr black holes.

Contribution

It demonstrates the focussing and reflection properties of particles and electromagnetic waves when colliding with the gravitational wave from a high-speed black hole, providing new insights into wave interactions.

Findings

Particles exhibit similar focussing as high-speed scattering by black holes.

Photons are reflected within a circular disk on the wave front.

Reflected electromagnetic waves are high frequency.

Abstract

The light-like limit of the Kerr gravitational field relative to a distant observer moving rectilinearly in an arbitrary direction is an impulsive plane gravitational wave with a singular point on its wave front. By colliding particles with this wave we show that they have the same focussing properties as high speed particles scattered by the original black hole. By colliding photons with the gravitational wave we show that there is a circular disk, centered on the singular point on the wave front, having the property that photons colliding with the wave within this disk are reflected back and travel with the wave. This result is approximate in the sense that there are observers who can see a dim (as opposed to opaque) circular disk on their sky. By colliding plane electromagnetic waves with the gravitational wave we show that the reflected electromagnetic waves are the high frequency waves.