Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 151-159).Observations of gravitational systems agree well with the predictions of general relativity (GR); however, to date we have only tested gravity in the weak-field limit. In the next few years, observational advances may make it possible for us to observe motion in the strong field for the first time. This thesis is concerned with two probes of strong-field gravity: whether the spacetime of a black hole has the structure predicted by GR, and the effect of spin-curvature coupling on orbital motion in the large mass-ratio limit. The first two-thirds of this thesis develop a formalism for determining whether a candidate black hole is described by the Kerr metric, as predicted by GR for all black holes in vacuum. In the first chapter, we describe how to construct a "bumpy black hole," an object whose spacetime is almost, but not quite, the Kerr metric. We define perturbations to the mass and spin moments and relate the changes in the moments to changes in the orbital frequencies using canonical perturbation theory. In the second chapter, we extend the bumpy black hole formalism to include black holes in non-GR theories of gravity, which leads to additional functional degrees of freedom. The final chapter investigates the effects of spin-curvature coupling. For a small body with spin moving around a massive black hole, the spin of the small body couples to the background curvature, and its trajectory deviates from a geodesic. To date, there has been relatively little work that considers this effect except in the special cases of aligned spins and circular, equatorial orbits. We compute the perturbation to the trajectory and the spin precession due to spin-curvature coupling for generic orbits of Kerr and arbitrary initial spin orientations.by Sarah Jane Vigeland.Ph.D
