Editors: Pau Amaro-Seoane & Bernard Schutz
The last GW Note is a Special Issues on eLISA/NGO

Binary Disruption by Massive Black Holes: Hypervelocity Stars, S Stars, and Tidal Disruption Events


by Bromley, Benjamin C. and Kenyon, Scott J. and Geller, Margaret J. and Brown, Warren R.
ApJ Letters, accepted; 13 pages, including 3 figures

We examine whether disrupted binary stars can fuel black hole growth. In this mechanism, tidal disruption produces a single hypervelocity star (HVS) ejected at high velocity and a former companion star bound to the black hole. After a cluster of bound stars forms, orbital diffusion allows the black hole to accrete stars by tidal disruption at a rate comparable to the capture rate. In the Milky Way, HVSs and the S star cluster imply similar rates of 10^{-5}–10^{-3} yr^{-1} for binary disruption. These rates are consistent with estimates for the tidal disruption rate in nearby galaxies and imply significant black hole growth from disrupted binaries on 10 Gyr time scales.

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