Cosmic Shear with Einstein Rings

TL;DR

This paper proposes using a collection of Einstein rings as a new statistical method to measure cosmic shear, potentially achieving precision comparable to current weak lensing surveys and offering complementary systematic advantages.

Contribution

It introduces a novel technique leveraging Einstein rings as a statistical probe of cosmic shear, expanding the toolkit for cosmological measurements.

Findings

Future surveys could match current weak lensing precision

The method is sensitive to different systematics than standard techniques

Einstein rings can serve as a complementary cosmological probe

Abstract

We explore a new technique to measure cosmic shear using Einstein rings. In Birrer et al. (2017), we showed that the detailed modelling of Einstein rings can be used to measure external shear to high precision. In this letter, we explore how a collection of Einstein rings can be used as a statistical probe of cosmic shear. We present a forecast of the cosmic shear information available in Einstein rings for different strong lensing survey configurations. We find that, assuming that the number density of Einstein rings in the COSMOS survey is representative, future strong lensing surveys should have a cosmological precision comparable to the current ground based weak lensing surveys. We discuss how this technique is complementary to the standard cosmic shear analyses since it is sensitive to different systematic and can be used for cross-calibration.