Coalescing binary black holes experience an impulsive kick due to anisotropic emission of gravitational waves. We discuss the dynamical consequences of the recoil accompanying massive black hole mergers. Recoil velocities are sufficient to eject most coalescing black holes from dwarf galaxies and globular clusters, which may explain the apparent absence of massive black holes in these systems. Ejection from giant elliptical galaxies would be rare, but coalescing black holes are displaced from the center and fall back on a time scale of order the half-mass crossing time. Displacement of the black holes transfers energy to the stars in the nucleus and can convert a steep density cusp into a core. Radiation recoil calls into question models that grow supermassive black holes from hierarchical mergers of stellar-mass precursors.

Publication Date



This is the pre-print of an article published by the American Astronomical Society. The final, published version is available here: https://doi.org/10.1086/421551

© 2004 The American Astronomical Society

Also archived in: arXiv:astro-ph/0402057 v2 9 Apr 2004

DM is supported by NSF grant AST02-0631, NASA grant NAG5-9046, and grant HST-AR-09519.01-Afrom STScI.MMis supported by a postdoctoral fellowship from the Sherman Fairchild Foundation. MF is partly supported by NSF grant PHY-0140209. SAH is supported by NASA grant NAG5-12906 and by NSF grant PHY-0244424. DH is supported by NSF grant PHY-0114422.

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Document Type


Department, Program, or Center

School of Physics and Astronomy (COS)


RIT – Main Campus