Towards cosmology with Void Lensing: how to find voids sensitive to weak-lensing and numerically interpret them

TL;DR

This paper introduces a new void-finder algorithm optimized for weak-lensing studies, compares it with existing methods, and investigates the consistency of lensing signals with dark matter profiles, revealing size-dependent discrepancies.

Contribution

The study presents a novel void-finder algorithm tailored for weak-lensing analysis and evaluates its effectiveness compared to traditional methods using realistic galaxy mocks.

Findings

Deeper weak-lensing profiles with the new algorithm.

Consistency between shear measurements and dark matter profiles for smaller voids.

Size-dependent discrepancies in lensing signals for large voids.

Abstract

In this work, we present a study of the void lensing signal or the excess surface mass density (ESMD) around cosmic voids. First, we propose a new void-finder algorithm that is designed to capture the ESMD around voids. We compare our algorithm applied to projected slices with the ZOBOV void finder and find significantly deeper weak-lensing profiles for voids defined by our algorithm in the context of a realistic galaxy mock. Then we test the consistency between the measurements of the ESMD as measured through the shear of background galaxies and directly calculated through the dark matter density profiles of the same voids. We found inconsistencies for voids with diameter $\geq 100h^{-1}\mathrm{Mpc}$ along the line-of-sight, but the consistency holds for smaller voids, meaning that we are indeed probing the underlying dark matter field by measuring the shear around these voids. Moreover, we show that voids found in the projected slices, which are highly sensitive to lensing, are correlated to $3$D voids exhibiting intrinsic alignments between them.