Correlated magnetic noise in global networks of gravitational-wave interferometers: observations and implications

TL;DR

This paper investigates correlated magnetic noise from Schumann resonances in global gravitational-wave detector networks, assessing its impact on stochastic background searches and providing constraints on environmental magnetic coupling.

Contribution

It provides the first measurements of correlated magnetic noise across LIGO and Virgo, and evaluates its implications for current and future gravitational-wave detectors.

Findings

Correlated magnetic noise is negligible for initial LIGO.

It could significantly affect Advanced LIGO and third-generation detectors.

Constraints on magnetic coupling to test masses are established.

Abstract

One of the most ambitious goals of gravitational-wave astronomy is to observe the stochastic gravitational-wave background. Correlated noise in two or more detectors can introduce a systematic error, which limits the sensitivity of stochastic searches. We report on measurements of correlated magnetic noise from Schumann resonances at the widely separated LIGO and Virgo detectors. We investigate the effect of this noise on a global network of interferometers and derive a constraint on the allowable coupling of environmental magnetic fields to test mass motion in gravitational-wave detectors. We find that while correlated noise from global electromagnetic fields could be safely ignored for initial LIGO stochastic searches, it could severely impact Advanced LIGO and third-generation detectors.