A coincidence null test for Poisson-distributed events

Abstract

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 gravitationalwave 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.

Detector Characterization and Mitigation of Noise in Ground-Based Gravitational-Wave Interferometers

“…This is done by examining a wide array of witness sensors to understand if they are correlated with the observed strain power. Multiple methods are used to identify correlations, including manual inspections of visualizations of data [41,42,[101][102][103], machine-learning interpretation of the strain data [47][48][49], tools that estimate statistical correlations between channels [50,52,53,104,105], and projections of the excess power in the observed strain data based on previous measurements between each auxiliary channel and the strain data [25,60,61].…”

LIGO Detector Characterization in the Second and Third Observing Runs

“…Algorithms such as the pointy statistic [72] and HVeto then run analyses on the hardware injections to generate lists of safe and unsafe channels. pointy is a null-test that uses the assumption that events in auxiliary channels are distributed according to stationary Poisson processes.…”

Application of a new transient-noise analysis tool for an unmodeled gravitational-wave search pipeline

“…In order to identify the origin of glitches driven from terrestrial disturbances, a set of system control sensors and environmental monitors that do not causally follow from the detector's output (so-called safe auxiliary channels) is used. To identify safe channels, LIGO uses hVETO [7] and Pointy Poison [8].…”