Void Lensing in Cubic Galileon Gravity

TL;DR

This study uses ray-tracing and N-body simulations to analyze weak lensing signals around cosmic voids in Cubic Galileon gravity, finding that future surveys could distinguish it from General Relativity.

Contribution

It introduces a combined N-body and ray-tracing methodology to realistically measure void lensing signals in Modified Gravity models, especially those affecting deflection angles.

Findings

Good agreement between measurement and theory for ESD in CG gravity

Lensing signals are more influenced by structure formation than deflection angle changes

Next-generation surveys could differentiate CG from GR

Abstract

Weak lensing studies via cosmic voids are a promising probe of Modified Gravity (MG). Excess surface mass density (ESD) is widely used as a lensing statistic in weak lensing research. In this paper, we use the ray-tracing method to study the ESD around voids in simulations based on Cubic Galileon (CG) gravity. With the compilation of N-body simulation and ray-tracing method, changes in structure formation and deflection angle resulting from MG can both be considered, making the extraction of lensing signals more realistic. We find good agreements between the measurement and theoretical prediction of ESD for CG gravity. Meanwhile, the lensing signals are much less affected by the change of the deflection angle than the change of the structure formation, indicating a good approximation of regarding ESD (statistics) as the projection of 3D dark matter density field. Finally, we demonstrate that it is impossible to distinguish CG and General Relativity in our simulation, however, in the next-generation survey, thanks to the large survey area and the increased galaxy number density, detecting the differences between these two models is possible. The methodology employed in this paper that combines N-body simulation and ray-tracing method can be a robust way to measure the lensing signals from simulations based on the MGs, and especially on that which significantly modifies the deflection angle.