Distinguishing Polarizations in Continuous Gravitational Waves
Mentor:Alan Weinstein, Professor of Physics, California Institute of Technology
According to the General Theory of Relativity, gravitational waves (GWs) can present only two polarizations, both of them transverse to the direction of wave propagation. This is generally taken as an assumption in the models used in the simulations and searches of gravitational waves. However, Einstein's theory has never been tested in the highly dynamical regime of GWs and alternative theories allow for the existence of as many as five distinct polarizations. In light of this, we develop methods to identify signals containing all such polarizations in continuous GWs emitted by spinning neutron stars, the Crab pulsar in particular. We analyze the extent to which extra polarizations can be detected, making use of simulated signals and preliminary searches in actual data from the LIGO gravitational wave detectors.