Detecting Cosmic Gravitational-wave Background from Super-heavy Cosmic Strings with LISA

TL;DR

This paper develops an algorithm to detect the cosmic gravitational-wave background generated by super-heavy cosmic strings using LISA data, establishing detection thresholds and parameter space for this elusive signal.

Contribution

It introduces a novel algorithm for extracting cosmic string signals from LISA data and assesses detection thresholds across various cosmic string parameters.

Findings

Detection threshold of Gμ is 3.12×10^-16 for 1-year observation.

Detectable parameter space defined by (Gμ)^2/3 ε^-1/3 / p > 4.6×10^-11.

Algorithm successfully identifies cosmic string background in simulated LISA data.

Abstract

Although cosmic string scenario for galaxy formation is disfavored by CMB data, it is of great interest in the generation of cosmic gravitational-wave background. This research aims to develop an algorithm to extract cosmic gravitational-wave background produced by cosmic strings from the LISA data stream, and apply the algorithm to the simulated data stream containing the background produced by cosmic strings with various strength to study the detection threshold for this source. For 1-yr observation, It is found that the detection threshold of G{\mu} is 3.12 \times 10^-16 in the standard scenario. In the case that p and {\epsilon} are adjustable, the detectable region in parameter space is defined by (G{\mu})^2/3 {\epsilon}^-1/3 / p> 4.6 \times 10-11.