Utilizing gravitational-wave (GW) lensing opens a new way to understand the small-scale structure of the universe. We show that, in spite of its coarse angular resolution and short duration of observation, LIGO can detect the GW lensing induced by compact structures, in particular by compact dark matter (DM) or primordial black holes of 10−105M⊙, which remain interesting DM candidates. The lensing is detected through GW frequency chirping, creating the natural and rapid change of lensing patterns: \emph{frequency-dependent amplification and modulation} of GW waveforms. As a highest-frequency GW detector, LIGO is a unique GW lab to probe such light compact DM. With the design sensitivity of Advanced LIGO, one-year observation by three detectors can optimistically constrain the compact DM density fraction fDM to the level of a few percent.
@article{arxiv.1712.01396,
title = {Gravitational-Wave Fringes at LIGO: Detecting Compact Dark Matter by Gravitational Lensing},
author = {Sunghoon Jung and Chang Sub Shin},
journal= {arXiv preprint arXiv:1712.01396},
year = {2019}
}
Comments
6 pages, 5 figures, v2: published version, Fig.5 updated with Poisson distribution, improved discussion on the optical depth