Deformation of horizons during a merger

Abstract

We model an extreme mass ratio merger (EMR) as a point particle radially plunging into a large Schwarzschild black hole. We assume that the mass of the point particle, $\mu$, is much smaller than the black hole mass M. Under this assumption we can employ the Zerilli formalism modified to include a source term which arises from the energy-momentum tensor of the small object. We solve the Zerilli equation by numerically evolving initial data. Then, we ray trace the null geodesics of the event horizon from after the merger backward in time to extract the geometry of the perturbed event horizon. Further, we take advantage of the axisymmetry of the setup to locate the apparent horizon and study its geometry.