Physical instrumental vetoes for gravitational-wave burst triggers

TL;DR

This paper introduces a physical veto strategy for gravitational-wave detectors that uses transfer functions and consistency tests to identify and exclude instrumental glitches, improving data quality with minimal false vetoes.

Contribution

The paper presents a novel, transfer function-based veto method that effectively distinguishes instrumental glitches from true gravitational-wave signals in detector data.

Findings

High veto efficiency demonstrated with hardware-injected glitches

Low accidental veto rate achieved in GEO 600 data

Method validated with hardware and GW-like injections

Abstract

We present a robust strategy to \emph{veto} certain classes of instrumental glitches that appear at the output of interferometric gravitational-wave (GW) detectors.This veto method is `physical' in the sense that, in order to veto a burst trigger, we make use of our knowledge of the coupling of different detector subsystems to the main detector output. The main idea behind this method is that the noise in an instrumental channel X can be \emph{transferred} to the detector output (channel H) using the \emph{transfer function} from X to H, provided the noise coupling is \emph{linear} and the transfer function is \emph{unique}. If a non-stationarity in channel H is causally related to one in channel X, the two have to be consistent with the transfer function. We formulate two methods for testing the consistency between the burst triggers in channel X and channel H. One method makes use of the \emph{null-stream} constructed from channel H and the \emph{transferred} channel X, and the second involves cross-correlating the two. We demonstrate the efficiency of the veto by `injecting' instrumental glitches in the hardware of the GEO 600 detector. The \emph{veto safety} is demonstrated by performing GW-like hardware injections. We also show an example application of this method using 5 days of data from the fifth science run of GEO 600. The method is found to have very high veto efficiency with a very low accidental veto rate.