Figure 7

Figure 7: This figure shows two views of the numerically-computed event horizon’s cross-section in the orbital plane for a spiraling binary black hole collision. The two orbital-plane dimensions are shown horizontally; time runs upwards. The initial data was constructed to have an approximate helical Killing vector, corresponding to black holes in approximately circular orbits (the D = 18 case of Grandclément et al. [78]), with a proper separation of the apparent horizons of 6.9 m. (The growth of the individual event horizons by roughly a factor of 3 in the first part of the evolution is an artifact of the coordinate choice – the black holes are actually in a quasi-equilibrium state.) Figure courtesy of Peter Diener.