A coincidence null test for Poisson-distributed events

When transient events are observed with multiple sensors, it is often necessary to establish the significance of coincident events. We derive a universal null test for an arbitrary number of sensors motivated by the archetypal detection problem for independent Poisson-distributed events in gravitational-wave detectors such as LIGO and Virgo. In these detectors, transient events may be witnessed by myriad channels that record interferometric signals and the surrounding physical environment. We apply our null test to a broad set of simulated gravitational-wave events as well as to a real gravitational-wave detection to determine which auxiliary channels do and do not witness real gravitational waves, and therefore which are safe to use when constructing vetoes. We also describe how our approach can be used to study detector artifacts and their origin, as well as to quantify the statistical independence of candidate gravitational-wave signals from noise artifacts observed in auxiliary channels.

Automated summary

A universal null test for transient events observed with multiple sensors is derived and applied to simulated and real gravitational-wave events, to determine the significance of coincident events and identify which auxiliary channels witness real gravitational waves. Additionally, this approach can be used to study detector artifacts, quantify the statistical independence of candidate gravitational-wave signals, and determine the safety of auxiliary channels for constructing vetoes.