A new general purpose event horizon finder for 3D numerical spacetimes

TL;DR

This paper introduces a versatile 3D event horizon finder that evolves a null surface backwards in time, capable of handling black hole mergers by allowing topology changes in the surface representation.

Contribution

It presents a novel method for locating event horizons in 3D numerical spacetimes using a scalar level set approach that can handle topology changes during mergers.

Findings

Successfully tracks black hole mergers in simulations

Handles topology changes in event horizon surfaces

Provides a general-purpose tool for numerical relativity

Abstract

I present a new general purpose event horizon finder for full 3D numerical spacetimes. It works by evolving a complete null surface backwards in time. The null surface is described as the zero level set of a scalar function, that in principle is defined everywhere. This description of the surface allows the surface, trivially, to change topology, making this event horizon finder able to handle numerical spacetimes, where two (or more) black holes merge into a single final black hole.