Wolfgang Tichy

Numerical simulation of orbiting black holes

One of the fundamental problems of general relativity is the two body problem of black holes in orbit. Since in general relativity two orbiting bodies emit gravitational waves that carry away energy and momentum from the system, the two black holes spiral inward and eventually merge. The last few orbits of a black hole binary fall into the strongly dynamic and non-linear regime of general relativity, and we therefore turn to numerical simulations to solve the full Einstein equations. Such numerical simulations have seen many advances in the last few years.

The picture shows the results from the first successful simulation that lasted for about one orbit. The black holes are shown in black together with the (color coded) lapse function in the orbital plane.

Using the moving puncture approach, it is now possible to evolve compact-object binaries through many orbits, merger and the ringdown of the final black hole. You can click on the pictures below to view short movies about the merger of two equal mass black holes.

Lapse function Gravitational wave BSSN phi on right side of grid