Ray-traced weak lensing convergence in screened modified gravity theories

Fuente: arXiv
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Autori principali: Pantiri, Mattia, Schaller, Matthieu, Silvestri, Alessandra, Broxterman, Jeger C., Schaye, Joop
Natura: Preprint
Pubblicazione: 2026
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author Pantiri, Mattia
Schaller, Matthieu
Silvestri, Alessandra
Broxterman, Jeger C.
Schaye, Joop
author_facet Pantiri, Mattia
Schaller, Matthieu
Silvestri, Alessandra
Broxterman, Jeger C.
Schaye, Joop
contents Weak gravitational lensing is one of the primary cosmological probes, providing powerful constraints on the cosmological model. As Stage IV surveys are expected to deliver data of unprecedented precision, accurate modeling of weak gravitational lensing observables across both linear and non-linear scales becomes increasingly important. In this work, we investigate weak lensing in modified gravity (MG) models, extensions of the standard $Λ$CDM cosmology in which gravity deviates from general relativity, generally introducing modifications to the lensing equation. We parametrize these modifications through the common phenomenological function $Σ_\mathrm{mg}$ and apply ray-tracing to the density maps of N-body and hydrodynamical simulations. We model the time dependence of $Σ_\mathrm{mg}$ analytically, while we introduce a phenomenological scale dependence to represent the screening mechanisms by which MG models reduce to general relativity in high-density environments. Starting from the output of the FLAMINGO hydrodynamical simulations, we generate fully ray-traced convergence maps using our modified lensing model. We analyze how the parameters of our prescription affect the weak lensing convergence power spectrum and compare these effects to other known sources of variation, in particular cosmological parameters and baryonic feedback. We find that the modifications to the lensing equation deriving from the MG model produce non-negligible signatures in the convergence power spectrum and that, within extensions of the $Λ$CDM framework, these effects can be larger than those induced by baryonic physics. Our results indicate that modified lensing should become a standard ingredient of the analysis of modified gravity simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2604_08393
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ray-traced weak lensing convergence in screened modified gravity theories
Pantiri, Mattia
Schaller, Matthieu
Silvestri, Alessandra
Broxterman, Jeger C.
Schaye, Joop
Cosmology and Nongalactic Astrophysics
Weak gravitational lensing is one of the primary cosmological probes, providing powerful constraints on the cosmological model. As Stage IV surveys are expected to deliver data of unprecedented precision, accurate modeling of weak gravitational lensing observables across both linear and non-linear scales becomes increasingly important. In this work, we investigate weak lensing in modified gravity (MG) models, extensions of the standard $Λ$CDM cosmology in which gravity deviates from general relativity, generally introducing modifications to the lensing equation. We parametrize these modifications through the common phenomenological function $Σ_\mathrm{mg}$ and apply ray-tracing to the density maps of N-body and hydrodynamical simulations. We model the time dependence of $Σ_\mathrm{mg}$ analytically, while we introduce a phenomenological scale dependence to represent the screening mechanisms by which MG models reduce to general relativity in high-density environments. Starting from the output of the FLAMINGO hydrodynamical simulations, we generate fully ray-traced convergence maps using our modified lensing model. We analyze how the parameters of our prescription affect the weak lensing convergence power spectrum and compare these effects to other known sources of variation, in particular cosmological parameters and baryonic feedback. We find that the modifications to the lensing equation deriving from the MG model produce non-negligible signatures in the convergence power spectrum and that, within extensions of the $Λ$CDM framework, these effects can be larger than those induced by baryonic physics. Our results indicate that modified lensing should become a standard ingredient of the analysis of modified gravity simulations.
title Ray-traced weak lensing convergence in screened modified gravity theories
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.08393