MSc Thesis Presentation: Gauge Freedom and Tidal Interactions in Compact Binary Systems

MSc Thesis Presentation

Candidate: Eamonn Corrigan

Abstract

The study of compact binary tidal interactions has become a very active area of research in recent years, encouraged further by the detection of gravitational wave signals from laser interferometers. Tidal deformations of material bodies should measurably alter the gravitational wave signals detected, teaching us about the internal structure of these compact objects. To explore these effects, one can carry out a matching calculation stitching together the near field metric from black hole perturbation theory with a Post-Newtonian expansion far from the deformed body. This work looks to simplify these lengthy calculations by taking advantage of the gauge freedom present in perturbation theory. We explore two different options: the EZ gauge, originally developed by Steven Detweiler, and the widely used Regge-Wheeler gauge. We discover the EZ gauge, unfortunately, does not aid in these calculations. It also includes an unavoidable singularity at the event horizon, further limiting its usefulness. The Regge-Wheeler gauge, however, does maintain the form of a Post-Newtonian metric when transformed, a result which drastically simplifies the matching procedure.

Examination Committee:

• Dr. Robert Wickham, Chair
• Dr. Eric Poisson, Advisor
• Dr. Bernard Nickel
• Dr. Luis Lehner