Nonlinear Weak Lensing reconstruction for Galaxy Clusters

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Hauptverfasser: Shi, Yuan, Cui, Li
Format: Preprint
Veröffentlicht: 2026
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author Shi, Yuan
Cui, Li
author_facet Shi, Yuan
Cui, Li
contents We present a numerical investigation of nonlinear cluster lens reconstruction using weak lensing mass mapping. Recent advances in imaging and shear estimation have pushed reliable reduced shear measurements closer to cluster cores, making mass reconstruction accessible in the nonlinear regime. However, the Kaiser-Squires based algorithm becomes unstable in cluster cores, where convergence $κ$ significantly deviates from zero and the linear approximation breaks down. To address this limitation, we develop a reconstruction framework with two key modifications: applying smooth masks to these regions and using a model-derived analytical solution as the initial guess, rather than assuming $κ= 0$. We validate our framework using simulated cluster lensing data with known mass distributions, incorporating realistic masks that arise from limitations in reduced shear measurements. We show that in the absence of shape noise, our framework yields high-fidelity mass reconstruction in regions of large reduced shear, with the best-performing method achieving residuals below $0.02 σ$ in the unmasked regions. This pushes mass reconstruction to higher accuracy in the nonlinear regime.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02816
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Nonlinear Weak Lensing reconstruction for Galaxy Clusters
Shi, Yuan
Cui, Li
Cosmology and Nongalactic Astrophysics
We present a numerical investigation of nonlinear cluster lens reconstruction using weak lensing mass mapping. Recent advances in imaging and shear estimation have pushed reliable reduced shear measurements closer to cluster cores, making mass reconstruction accessible in the nonlinear regime. However, the Kaiser-Squires based algorithm becomes unstable in cluster cores, where convergence $κ$ significantly deviates from zero and the linear approximation breaks down. To address this limitation, we develop a reconstruction framework with two key modifications: applying smooth masks to these regions and using a model-derived analytical solution as the initial guess, rather than assuming $κ= 0$. We validate our framework using simulated cluster lensing data with known mass distributions, incorporating realistic masks that arise from limitations in reduced shear measurements. We show that in the absence of shape noise, our framework yields high-fidelity mass reconstruction in regions of large reduced shear, with the best-performing method achieving residuals below $0.02 σ$ in the unmasked regions. This pushes mass reconstruction to higher accuracy in the nonlinear regime.
title Nonlinear Weak Lensing reconstruction for Galaxy Clusters
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2601.02816