Binary Black Hole Merger in Galactic Nuclei: Post-Newtonian Simulations

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This paper studies the formation and evolution of binary supermassive black holes (SMBHs) in rotating galactic nuclei, focusing on the role of stellar dynamics.

• We present the first N-body simulations that follow the evolution of the SMBHs from kiloparsec separations all the way to their final relativistic coalescence, and that can robustly be scaled to real galaxies.
• The N-body code includes post-Newtonian (PN) corrections to the binary equations of motion up to order 2.5; we show that the evolution of the massive binary is only correctly reproduced if the conservative 1PN and 2PN terms are included.
• The orbital eccentricities of the massive binaries in our simulations are often found to remain large until shortly before coalescence.