Collisions of black holes: Cracks in a hard problem

Abstract

I outline recently published progress in the evolution of binary black hole space-times, using a method that excises the singular regions inside the apparent horizons. This includes a new method for setting data for moving black holes, and the simulation of non-headon (grazing) collisions of binary black holes in which the black hole singularities have been excised from the computational domain. I describe an evolution of up to t≈35m involving two equal mass spinning black holes m in which two initially separate apparent horizons are present for t≈3.8m. At that time a single enveloping apparent horizon forms, indicating that the holes have merged. Apparent horizon area estimates suggest gravitational radiation of about 2%–3% of the total mass. The evolutions end after a moderate amount of time because of instabilities.