Revisiting Stochastic Gravitational-wave Background in the Strong Signal Case

• DOI: 10.48550/arxiv.2403.18709
• Publication Date: 2024-03-27
• Authors: Zheng-Cheng Liang; Zhiyuan Li; En-Kun Li; Jian-dong Zhang; Yi-Ming Hu
• Keywords: Gravitational wave background; SIGNAL (programming language)

Weak-signal limit is often used in estimating stochastic gravitational-wave background (SGWB) intensities. This approximation fails and the signal-to-noise ratio (SNR) can be much weaker when signals are loud compared to detector noise. In this work, we highlight limitation for SGWB detection using space-borne networks. For TianQin + LISA network, SNR estimated under weak-signal might off by as large an order of magnitude. Contour plots over parameter spaces also presented indicate regions susceptible discrepancy. Our results suggest that DA DB type extragalactic double white dwarfs may yield with surpassing 100 after 1 year operation weak-signal-limit scenario, a redshift-independent merger rate about $500\,\,{\rm Mpc^{-3}\,Myr^{-1}}$. fact, value falls significantly below necessary threshold. Similar influences arise first-order phase transitions, yet pinning down remains formidable due model uncertainties.