Treatment of Calibration Uncertainty in Multi-Baseline Cross-Correlation Searches for Gravitational Waves

TL;DR

This paper addresses how to properly incorporate calibration uncertainties from multiple gravitational-wave detectors into cross-correlation searches for stochastic backgrounds, improving the reliability of signal detection limits.

Contribution

It introduces a method to account for correlations between calibration uncertainties across multiple detector pairs by marginalizing over individual instrument uncertainties.

Findings

Enhanced calibration uncertainty treatment for multi-baseline GW networks

Improved accuracy in setting limits on GW signals

Framework applicable to current and future GW detector networks

Abstract

Uncertainty in the calibration of gravitational-wave (GW) detector data leads to systematic errors which must be accounted for in setting limits on the strength of GW signals. When cross-correlation measurements are made using data from a pair of instruments, as in searches for a stochastic GW background, the calibration uncertainties of the individual instruments can be combined into an uncertainty associated with the pair. With the advent of multi-baseline GW observation (e.g., networks consisting of multiple detectors such as the LIGO observatories and Virgo), a more sophisticated treatment is called for. We describe how the correlations between calibration factors associated with different pairs can be taken into account by marginalizing over the uncertainty associated with each instrument.