Gravitational Wave Sirens as a Triple Probe of Dark Energy

TL;DR

This paper explores how gravitational wave standard sirens, when analyzed through lensing noise, can simultaneously probe cosmic expansion, structure growth, and dark energy properties, offering a multi-faceted approach to cosmology.

Contribution

It introduces a novel method of using lensing noise measurements as signals to probe cosmology, including a new lensing probability function and analysis of minimum convergence bias.

Findings

Lensing noise can serve as a signal for cosmological measurements.

A new lensing probability function is proposed.

Standard sirens and candles together can triple-probe dark energy.

Abstract

Gravitational wave standard sirens have been considered as precision distance indicators to high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a highly complementary manner to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.