Double Source Lensing Probing High Redshift Cosmology

TL;DR

Double source lensing at high redshifts, enabled by upcoming surveys, offers a promising method to probe dark energy properties and density evolution with reduced model sensitivity.

Contribution

This paper demonstrates the potential of high-redshift double source lensing to constrain dark energy parameters and density evolution, leveraging future survey data.

Findings

Dark energy figure of merit of 245 from 256 systems.

Potential to detect dark energy density up to redshift 5.

Measurements can achieve significance levels between 2.5σ and 31σ.

Abstract

Double source lensing, with two sources lensed by the same foreground galaxy, involves the distance between each source and the lens and hence is a probe of the universe away from the observer. The double source distance ratio also reduces sensitivity to the lens model and has good complementarity with standard distance probes. We show that using this technique at high redshifts $z>1$, to be enabled by data from the Euclid satellite and other surveys, can give insights on dark energy, both in terms of $w_0$-$w_a$ and redshift binned density. We find a dark energy figure of merit of 245 from combination of 256 double source systems with moderate quality cosmic microwave background and supernova data. Using instead five redshift bins between $z=1.1$-5, we could detect the dark energy density out to $z\approx5$, or make measurements ranging between 31$\sigma$ and 2.5$\sigma$ of its values in the bins.