The dark timbre of gravitational waves

TL;DR

This paper explores how gravitational wave timbre, influenced by low-mass dark matter halos, can be used to detect small halos in the universe using LISA observations of binary systems.

Contribution

It demonstrates that the lensing effect on gravitational wave timbre can serve as a probe for low-mass dark matter halos in the universe.

Findings

Lensing of gravitational waves can reveal halos with masses below 10 solar masses.

Detection requires high signal-to-noise ratio and specific binary eccentricities.

Potential to probe dark matter structures at cosmological distances.

Abstract

Gravitational wave timbre, the relative amplitude and phase of the different frequency harmonics, can change due to interactions with low-mass halos. We focus on binaries in the LISA range and find that the integrated lens effect of cold dark matter structures can be used to probe the existence of $M_{\rm v}\lesssim 10\, M_{\odot}$ halos if a single binary with eccentricity $e=0.3-0.6$ is detected with a signal-to-noise ratio $100 - 10^3$ and it is at $z_s=0.5$.