The new generation lunar gravitational wave detectors: sky map resolution and joint analysis

TL;DR

This paper evaluates the angular resolution of lunar-based gravitational wave detectors, showing that a lunar observatory can outperform space missions in localization accuracy, especially with an upgraded tetrahedral configuration.

Contribution

It introduces the CIGO and TCIGO lunar gravitational wave detectors and assesses their sky localization performance compared to space-based missions.

Findings

CIGO outperforms TianQin and LISA above 0.1 Hz in localization accuracy.

Lunar noise mitigation is crucial for detector performance.

TCIGO offers five times better angular resolution than CIGO.

Abstract

Lunar-based gravitational-wave interferometry is a fascinating endeavor, and was proposed as a promising approach to bridge the observational gap between space-borne and ground-based detectors. In this work, we adopt the Fisher-matrix method to examine the angular-resolution performance of the newly proposed Crater Interferometry Gravitational-wave Observatory (CIGO) on the lunar crater rim near the north pole, together with TianQin and LISA, for monochromatic sources in the 0.1-10 Hz band. We find that above 0.1 Hz, CIGO achieves better localization accuracy than the other two space-based missions and dominates the combined detector network's performance, provided that lunar noise mitigation is achieved in the 0.1-2.87 Hz frequency range. We further explore an upgraded Tetrahedron configuration, TCIGO, with a fourth station at the bottom of a crater, which forms a regular tetrahedral constellation on the lunar surface. The result shows that TCIGO yields a five-fold improvement in angular-resolution capability over CIGO and gets better sky coverage across the target frequency band.