Coherent versus coincidence detection of gravitational wave signals from compact inspiraling binaries

TL;DR

This paper compares coherent and coincidence detection strategies for gravitational wave signals from compact binaries, finding that the coherent method generally outperforms coincidence approaches under ideal noise conditions.

Contribution

It provides a detailed comparison of detection strategies, introducing an enhanced coincidence method and demonstrating the superior performance of coherent detection in idealized scenarios.

Findings

Coherent detection outperforms coincidence strategies in Gaussian noise.

Enhanced coincidence improves detection for misaligned detectors.

Receiver operating characteristic curves show clear advantage of coherent method.

Abstract

We compare two multi-detector detection strategies, namely, the coincidence and the coherent, for the detection of spinless inspiraling compact binary gravitational wave signals. The coincident strategy treats the detectors as if they are isolated - compares individual detector statistics with their respective thresholds while the coherent strategy combines the detector network data {\it phase coherently} to obtain a single detection statistic which is then compared with a single threshold. In the case of geographically separated detectors, we also consider an {\it enhanced} coincidence strategy because the usual (naive) coincidence strategy yields poor results for misaligned detectors. For simplicity, we consider detector pairs having the same power spectral density of noise, as that of initial LIGO and also assume the noise to be stationary and Gaussian. We compare the performances of the methods by plotting the \emph{receiver operating characteristic} (ROC) for the two strategies. A single astrophysical source as well as a distribution of sources is considered. We find that the coherent strategy performs better than the two coincident strategies under the assumptions of stationary Gaussian detector noise.