Recoiling Black Holes in Static and Evolving Dark Matter Halo Potential

Abstract

We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. The considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study the critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ∼ 40% lower kick velocities can remove black holes from their host haloes at z = 7 compared to z = 1. The greatest difference between the static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ∼ 30% higher kick velocities are needed for complete removal of BHs from dark matter halo described by the NFW profile.