The role of gravitational recoil in the assembly of massive black hole
  seeds
  When two black holes merge, the asymmetric emission of gravitational waves
provides an impulse to the merged system; this gravitational wave recoil
velocity can be up to 4000 km s$^{-1}$, easily fast enough for the black hole
to escape its host galaxy. We combine semi-analytic modeling with cosmological
zoom-in simulations of a Milky Way-type galaxy to investigate the role of black
hole spin and gravitational recoil in the epoch of massive black hole seeding.
We sample four different spin distributions (random, aligned, anti-aligned, and
zero spin), and compare the resulting merger rates, occupation fractions, and
MBH-host relations with what is expected by excluding the effect of recoil. The
inclusion of gravitational recoil and MBH spin in the assembly of MBH seeds can
reduce the final $z=5$ MBH mass by up to an order of magnitude. The MBH
occupation fraction, however, remains effectively unaltered due to episodes of
black hole formation following a recoil event. While electromagnetic detections
of these events are unlikely, LISA is ideally suited to detect gravitational
wave signals from such events.
