The Effect of Higher Harmonics On Gravitational Wave Dark Sirens

TL;DR

This paper investigates how higher harmonics in gravitational wave signals improve the accuracy of distance measurements for black hole mergers, thereby enhancing cosmological parameter estimation with future detectors.

Contribution

It demonstrates that including higher harmonics significantly improves luminosity distance estimates for third-generation gravitational wave detectors.

Findings

Higher harmonics improve distance inference accuracy.

Enhanced distance estimates lead to better Hubble constant constraints.

Higher harmonics reduce degeneracy between distance and inclination.

Abstract

The gravitational wave (GW) signal from the merger of two black holes can serve as a standard sirens for cosmological inference. However, a degeneracy exists between the luminosity distance and the inclination angle between the binary system's orbital angular momentum and the observer's line of sight, limiting the precise measurement of the luminosity distance. In this study, we investigate how higher harmonics affect luminosity distance estimation for third-generation (3G) GW detectors in binary black hole mergers. Our findings demonstrate that considering higher harmonics significantly enhances distance inference results compared with using only the (2,2) mode. This improved accuracy in distance estimates also strengthens constraints on host galaxies, enabling more precise measurements of the Hubble constant. These results highlight the significant influence of higher harmonics on the range estimation accuracy of 3G ground-based GW detectors.