Physics Colloquium: The Beginning of an END

The anisotropic emission of gravitational waves during the merger of two supermassive black holes can result in a recoil kick of the merged remnant. We show, via analytic and N-body work, that eccentric nuclear disks — stellar disks of eccentric, apse-aligned orbits – can directly form as a result. An initially circular disk of stars will align orthogonal to the black hole kick direction with a distinctive “check-mark” eccentricity distribution and a spiral pattern in mean anomaly. A tidal disruption event occurs when a star gets too close to the central supermassive black hole and gets ripped apart by the tidal gravity of the black hole. In an eccentric disk, the rate of tidal disruption events is significantly elevated compared to an isotropic configuration which could explain the high tidal disruption event rates observed in post-starburst/merging galaxies. We discuss the evolution of eccentric nuclear disks and their corresponding tidal disruption event rates as a function of the gravitational recoil kick magnitude.