Weak lensing by voids in weak lensing maps

TL;DR

This paper introduces a novel method for detecting cosmic voids directly in weak lensing convergence maps, revealing larger shear signals than traditional galaxy-based void identification methods.

Contribution

It proposes a new paradigm for void detection in weak lensing maps, demonstrating advantages over galaxy-based methods and revealing self-similar void abundance and enhanced shear signals.

Findings

Void detection in lensing maps shows self-similarity across thresholds.

Lensing-identified voids produce up to 40 times larger shear signals.

The approach offers a direct link to the matter underdensities in large-scale structure.

Abstract

Cosmic voids are an important probe of large-scale structure that can constrain cosmological parameters and test cosmological models. We present a new paradigm for void studies: void detection in weak lensing convergence maps. This approach identifies objects that relate directly to our theoretical understanding of voids as underdensities in the total matter field and presents several advantages compared to the customary method of finding voids in the galaxy distribution. We exemplify this approach by identifying voids using the weak lensing peaks as tracers of the large-scale structure. We find self-similarity in the void abundance across a range of peak signal-to-noise selection thresholds. The voids obtained via this approach give a tangential shear signal up to $\sim40$ times larger than voids identified in the galaxy distribution.