Modulating the experimental signature of a stochastic gravitational wave backgroun

TL;DR

This paper proposes a new method to distinguish true stochastic gravitational wave signals from correlated instrumental noise by modulating detector orientation, improving measurement reliability for the ALLEGRO/LIGO Livingston pair.

Contribution

It introduces a technique to identify systematic errors from correlated noise by varying detector orientation, enhancing the accuracy of stochastic gravitational wave background measurements.

Findings

Method effectively separates signal from correlated noise.

Technique is applicable to ALLEGRO/LIGO Livingston detector pair.

Reduces systematic errors in stochastic background detection.

Abstract

Detecting a stationary, stochastic gravitational wave signal is complicated by impossibility of observing the detector noise independently of the signal. One consequence is that we require at least two detectors to observe the signal, which will be apparent in the cross-correlation of the detector outputs. A corollary is that there remains a systematic error, associated with the possible presence of correlated instrumental noise, in any observation aimed at estimating or limiting a stochastic gravitational wave signal. Here we describe a method of identifying this systematic error by varying the orientation of one of the detectors, leading to separate and independent modulations of the signal and noise contribution to the cross-correlation. Our method can be applied to measurements of a stochastic gravitational wave background by the ALLEGRO/LIGO Livingston Observatory detector pair. We explore -- in the context of this detector pair -- how this new measurement technique is insensitive to a cross-correlated detector noise component that can confound a conventional measurement.