Retaining Black Holes with Very Large Recoil Velocities

Understand

Recent numerical simulations of binary black hole mergers show the possibility of producing very large recoil velocities (> 3000 km/s).

• Kicks of this magnitude should be sufficient to eject the final black hole from virtually any galactic potential.
• This result has been seen as a potential contradiction with observations of supermassive black holes residing in the centers of most galaxies in the local universe.
• Using an extremely simplified merger tree model, we show that, even in the limit of very large ejection probability, after a small number of merger generations there should still be an appreciable fraction (>50%) of galaxies with supermassive black holes today.