Void Weak Lensing in modified gravity simulations

Cosmic voids, vast underdense regions in the universe, offer a unique opportunity to probe modified gravity theories. This study focuses on f(R) models, which mimic ΛCDM at high redshifts but diverge at low redshifts. By analyzing weak gravitational lensing from voids, small distortions in background light sources due to underdensity fluctuations, we aim to measure tangential shear profiles in f(R) models compared to ΛCDM. We develop a pipeline for identifying and analyzing 2D voids using cosmological simulations. Applying this to the DUSTGRAIN-pathfinder dataset, we extract void samples and compute shear profiles. Smaller voids exhibit deeper, rapidly rising signals compared to larger voids. In f(R) models, voids show more negative shear profiles due to enhanced evolution, while massive neutrinos result in shallower profiles due to structural growth damping. We propose a new parametric formula for void shear profiles, validated through Bayesian analysis. However, distinguishing between ΛCDM and alternative models remains challenging due to observational uncertainties. Future efforts will focus on larger simulations and real data catalogs to enhance void statistics and explore wider cosmological scenarios.