Figures of merit for a stochastic gravitational-wave background measurement by LISA: implications of LISA Pathfinder noise correlations

TL;DR

This paper assesses how correlated noise sources in LISA Pathfinder data could impact the Laser Interferometer Space Antenna's ability to detect a stochastic gravitational-wave background, providing a framework for noise mitigation.

Contribution

It introduces a method to evaluate the impact of correlated noise on LISA's SGWB measurement using realistic Pathfinder data and noise correlation analysis.

Findings

Correlated noise can significantly affect LISA's SGWB detection sensitivity.

Magnetic fields, temperature, and thruster activity are relevant noise sources.

The study provides a figure of merit to quantify noise impact on measurements.

Abstract

An important goal of the Laser Interferometer Space Antenna (LISA) is to observe a stochastic gravitational-wave background (SGWB). A study of possible correlated noise in LISA is relevant to establish limits for this future measurement. To test noise investigation methods under somewhat realistic conditions, we use the data of LISA Pathfinder (LPF). We calculate the coherence between the LPF differential acceleration of the two test-masses with magnetic fields, temperature, and micronewton cold gas thruster activity in the spacecraft. We apply our observed correlations to LISA, and estimate how the presence of such correlated noise would affect its search for a SGWB. In the context of a figure of merit, we estimate the effect of noise on the LISA SGWB search.