Reducing false alarms in searches for gravitational waves from coalescing binary systems

Abstract

LIGO observatories in Livingston, LA and Hanford, WA may detect gravitational waves emitted from coalescing binary systems composed of two compact objects. In order to detect compact binary coalescence (CBC) events, LIGO searches utilize matched filtering techniques. Matched filtering is the optimal detection strategy for stationary, Gaussian noise, however, LIGO noise is often non-stationary, non-Gaussian. Non-stationary noise result in an excess of false candidate events, commonly known as false alarms. This thesis develops the r2 test to reduce the false alarm rate for LIGO CBC searches. Results of the search for primordial black hole binary systems (where each object has less than 1Msolar), in LIGO's Third Science Run (S3) is also presented. Results of the r2 test are shown for several LIGO CBC searches, including the binary neutron star searches in the Third and Fourth Science Runs (S3/S4), the S3/S4 primordial black hole searches, and the binary black hole search in the first three months of the Fifth Science Run (S5). The r2 test significantly reduces the false alarm rate in these searches, while only falsely dismissing a small fraction of simulated events.