ITR: Numerical and Computational Tools for Binary Black Hole Simulations

Pennsylvania State Univ University Park, University Park PA

Investigators

Abstract

The goal is to provide new numerical and computational tools to reach a new milestone: performing computer simulations of the last fewinspiraling orbits of two black holes and their violent collision and merger. The dynamics of such a binary black hole system is governed by Einstein's equations for general relativity. To solve the very complex Einstein equations on the computer, special methods are developed that improve the computational efficiency so that fully three-dimensional simulations become possible on a routine basis. This requires taking the pecularities of Einstein's general relativity into account, in particular finding good explicit coordinates (so that the computer can handle the `everything is relative' of general relativity) and dealing with the spacetime singularities that lurk inside black holes. It is remarkable that even today the two body problem of general relativity still remains unsolved. Especially the problem of dynamics of two black holes in a binary has drawn considerable attention, but not even a single orbit of two black holes has been simulated. The orbital motion of black holes follows a spiral that leads to thecollision and merger of the black holes, which is expected to produce large amounts of gravitational radiation. The community of gravitational wave astronomers urgently awaits predictions for the merger waves of black holes from computer simulations.