Improving the sensitivity of searches for an association between gamma-ray bursts and gravitational waves

摘要

Gamma-ray burst (GRB) central engines are potentially strong gravitational wave (GW) sources. GRBs occur at the rate of similar to 1/day and several currently operating and planned observatories will maintain coverage of the gamma-ray window over the next decade. Data analysis strategies are required that can exploit multiple GRB triggers collected over a long span of time to expand the science reach of GW detectors beyond that possible with a single direct coincidence search. Such a strategy has been proposed earlier by Finn, Mohanty and Romano (FMR). In this paper, we formally derive, multi-GRB search algorithms from principles of Frequentist statistical decision theory. The FMR approach is shown to be a special case where the duration of the GW signal from a GRB is of the same order as its expected offset from the gamma-ray counterpart. A new ad hoc statistic, based on plausible arguments, is also constructed and compared with the formally derived one.