Efficient Merger of Binary Supermassive Black Holes in Nonaxisymmetric Galaxies

Binary supermassive black holes form naturally in galaxy mergers, but theirlong-term evolution is uncertain. In spherical galaxies, N-body simulationsshow that binary evolution stalls at separations much too large for significantemission of gravitational waves (the "final parsec problem"). Here, we followthe long-term evolution of a massive binary in more realistic, triaxial androtating galaxy models. We find that the binary does not stall. The binaryhardening rates that we observe are sufficient to allow complete coalescence ofbinary SBHs in 10 Gyr or less, even in the absence of collisional loss-conerefilling or gas-dynamical torques, thus providing a potential solution to thefinal parsec problem.Comment: 5 pages, 3 figure