Date of Award

December 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Duncan A. Brown


binary black holes, binary neutron stars, gravitational waves, neutron star black hole binaries

Subject Categories

Physical Sciences and Mathematics


We explore the detection and astrophysical modeling of gravitational waves de- tected by the Advanced Laser Interferometer Gravitational wave Observatory (LIGO) and Virgo. We discuss the techniques used in the PyCBC search pipeline to discover the first gravitational wave detection GW150914, and estimate the statistical signifi- cance of GW150914, and the marginal trigger LVT151012. During Advanced LIGO’s first observing run there were no detections of mergers from binary neutron star and neutron star-black hole binaries. We use Bayesian inference to place upper limits on the rate of coalescence of these binaries. We use developments made in the PyCBC search pipeline during Advanced LIGO and Virgo’s second observing run to re-analyze Advanced LIGO’s first observing run and re-estimate the statistical significance of LVT151012. We present sufficient evidence to claim LVT151012 as a gravitational wave event. In Advanced LIGO and Virgo’s 2nd observing run a gravitational wave due to the merger of two binary neutron stars, known as GW170817, was discov- ered. We develop tools for Bayesian hypothesis testing so that we can investigate the interior dynamics of neutron stars using the GW170817 signal. Finally, we use Bayesian parameter estimation from PyCBC with tools of Bayesian hypothesis testing to investigate the presence of nonlinear tidal dynamics from a pressure – gravity mode instability in GW170817. We find that significant waveform degeneracies allow the effect of nonlinear tides to be compatible with the data at the level of nonsignificance (Bayes factor of unity). We also investigate further constraints on these nonlinear tides.


Open Access