Simulation of binary black hole spacetimes with a harmonic evolution scheme

A numerical solution scheme for the Einstein field equations based on generalized harmonic coordinates is described, focusing on details which are not provided before in the literature and which are of particular relevance to the binary black hole problem. This includes demonstrations of the effectiveness of constraint damping, and how the time slicing can be controlled through the use of a source function evolution equation. In addition, some results from an ongoing study of binary black hole coalescence, where the black holes are formed via scalar field collapse, are shown. Scalar fields offer a convenient route to exploring certain aspects of black hole interactions, and one interesting though tentative suggestion from this early study is that behaviour reminiscent of 'zoom-whirl' orbits in particle trajectories is also present in the merger of equal mass, non-spinning binaries, with appropriately fine-tuned initial conditions.