- M J Rees
We investigated the evolution of the black hole binary formed by the merging of two galaxies each containing a central massive black hole. Our main goal here is to determine if the black hole binary can merge through the hardening by dynamical friction and the gravitational wave radiation. Using N-body simulation, we found that the evolution timescale is independent of the number of particles in the galaxy N until the semi-major axis reaches a critical value. After the semi-major axis became smaller than this critical value, the evolution timescale is longer for larger number of particles. Qualitatively, this behavior is understood naturally as the result the \loss-cone" eeect. However, the dependence of the timescale on N is noticeably weaker than the theoretical prediction.