  A supermassive black hole ejected from the center of a galaxy by
gravitational wave recoil carries a retinue of bound stars - a "hypercompact
stellar system" (HCSS). The numbers and properties of HCSSs contain information
about the merger histories of galaxies, the late evolution of binary black
holes, and the distribution of gravitational-wave kicks. We relate the
structural properties of HCSSs to the properties of their host galaxies, in two
regimes: collisional, i.e. short nuclear relaxation times; and collisionless,
i.e. long nuclear relaxtion times. HCSSs are expected to be similar in size and
luminosity to globular clustersbut in extreme cases their stellar mass can
approach that of UCDs. However they differ from all other classes of compact
stellar system in having very high internal velocities. We show that the kick
velocity is encoded in the velocity dispersion of the bound stars. Given a
large enough sample of HCSSs, the distribution of gravitational-wave kicks can
therefore be empirically determined. We combine a hierarchical merger algorithm
with stellar population models to compute the rate of production of HCSSs over
time and the probability of observing HCSSs in the local universe as a function
of their apparent magnitude, color, size and velocity dispersion, under two
assumptions about the star formation history prior to the kick. We predict that
roughly 100 should be detectable within 2 Mpc of the center of the Virgo
cluster and that many of these should be bright enough that their high internal
velocity dispersions could be measured with reasonable exposure times.
