Coalescing binary black holes experience a “kick” due to anisotropic emission of gravitational waves with an amplitude as great as ∼ 200 km s−1. We examine the orbital evolution of black holes that have been kicked from the centers of triaxial galaxies. Time scales for orbital decay are generally longer in triaxial galaxies than in equivalent spherical galaxies, since a kicked black hole does not return directly through the dense center where the dynamical friction force is highest. We evaluate this effect by constructing self-consistent triaxial models and integrating the trajectories of massive particles after they are ejected from the center; the dynamical friction force is computed directly from the velocity dispersion tensor of the self-consistent model. We find return times that are several times longer than in a spherical galaxy with the same radial density profile, particularly in galaxy models with dense centers, implying a substantially greater probability of finding an off-center black hole.

Publication Date



This is the pre-print of an article published by the American Astronomical Association. The final, published version is located here: https://doi.org/10.1086/518116

© 2007 The American Astronomical Society

Also archived in: arXiv:astro-ph/0612073 v2 Mar 22 2007

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

School of Physics and Astronomy (COS)


RIT – Main Campus