Time-Averaged Template for Stochastic Gravitational-Wave Background Detection in Space-Based Interferometers

TL;DR

This paper evaluates different template strategies for detecting the stochastic gravitational-wave background in space-based interferometers, emphasizing the importance of realistic modeling of arm-length variations for accurate parameter estimation.

Contribution

It introduces and compares three template construction methods, demonstrating that a time-averaged template improves accuracy in realistic orbital configurations.

Findings

Time-averaged template improves parameter estimation accuracy.

Treating arm-lengths as free parameters increases uncertainty.

Realistic template construction is crucial for future space missions.

Abstract

Stochastic gravitational-wave background (SGWB) poses significant challenges for data analysis and parameter inference in future space-based gravitational-wave missions, such as LISA and Taiji, as it appears as an additional stochastic component along with instrumental noise. Previous studies have developed various approaches to distinguish the SGWB from instrumental noise, often under simplified assumptions such as static or equal-arm configurations. However, in realistic scenarios, time-varying arm-lengths introduce additional complexities that require careful modeling. In this work, we investigate the impact of template construction on SGWB parameter estimation under realistic orbital configurations. Using the simulated SGWB signals and dominant instrumental noise sources, we compare three template strategies: time-averaged template constructed from segmented data, equal-arm template, and a template treating the arm-lengths as a free parameter. Our results show that the time-averaged template yield improves parameter estimation accuracy under time-varying arm-lengths, whereas introducing the effective arm-length as a free parameter increases estimation uncertainty. These findings highlight the importance of realistic template construction for high-precision SGWB analysis in future space-based missions.