Lens Stochastic Diffraction: A Signature of Compact Structures in Gravitational-Wave Data

TL;DR

This paper introduces lens stochastic diffraction (LSD), a method to detect and analyze faint gravitational wave signals caused by compact gravitational lenses, providing insights into dark matter and black holes.

Contribution

LSD offers an order-of-magnitude improvement over traditional methods for detecting compact lenses using gravitational waves, enabling better constraints on dark matter and black hole populations.

Findings

LSD can detect lenses with masses greater than 10^3 solar masses.

It improves detection sensitivity by an order of magnitude over single lens analysis.

Potential to identify supermassive black holes and constrain dark matter halos.

Abstract

Every signal propagating through the universe is diffracted by the gravitational fields of intervening objects, aka gravitational lenses. Diffraction is most efficient when caused by compact lenses, which invariably produce additional images of a source. The signals associated with additional images are generically faint, but their collective effect may be detectable with coherent sources, such as gravitational waves (GWs), where both amplitude and phase are measured. Here, I describe lens stochastic diffraction (LSD): Poisson-distributed fluctuations after GW events caused by compact lenses. The amplitude and temporal distribution of these signals encode crucial information about the mass and abundance of compact lenses. Through the collective stochastic signal, LSD offers an order-of-magnitude improvement over single lens analysis for objects with mass $\gtrsim 10^3 M_\odot$. This gain can improve limits on compact dark-matter halos and allows next-generation instruments to detect supermassive black holes, given the abundance inferred from quasar luminosity studies.