The Santiago–Harvard–Edinburgh–Durham void comparison II: unveiling the Vainshtein screening using weak lensing

Abstract

We study cosmic voids in the normal-branch Dvali-Gabadadze-Porrati (nDGP) braneworld models, which are representative of a class of modified gravity theories where deviations from General Relativity are usually hidden by the Vainshtein screening in high-density environments. This screening is less efficient away from these environments, which makes voids ideally suited for testing this class of models. We use N-body simulations of Λ-cold dark matter (ΛCDM) and nGDP universes, where dark matter haloes are populated with mock galaxies that mimic the clustering and number densities of the BOSS CMASS galaxy sample. We measure the force, density and weak lensing profiles around voids identified with six different algorithms. Compared to ΛCDM, voids in nDGP are more under-dense due to the action of the fifth force that arises in these models, which leads to a faster evacuation of matter from voids. This leaves an imprint on the weak lensing tangential shear profile around nDGP voids, an effect that is particularly strong for 2D underdensities that are identified in the plane-ofthe-sky. We make predictions for the feasibility of distinguishing between nDGP and ΛCDM using void lensing in upcoming large-scale surveys such as LSST and EUCLID. We compare with the analysis of voids in chameleon gravity theories and find that the weak lensing signal for 3D voids is similar to nDGP, whereas for 2D voids the differences with ΛCDM are much stronger for the chameleon gravity case, a direct consequence of the different screening mechanisms operating in these theories.

Dark Energy Survey year 1 results: the relationship between mass and light around cosmic voids

“…Colberg et al (2008) compared a total of 13 void finders identifying voids from the Millennium simulation. More recent studies by Cautun et al (2018) and Paillas et al (2019) compared various void definitions, focussing on their potential to differentiate between either Chameleon-, or Vainshteintype modified gravity and ΛCDM via weak lensing. But not only discrete tracer distributions have been considered for this purpose, as demonstrated by Davies et al (2018Davies et al ( , 2019 using weak-lensing maps and by Krolewski et al (2018) using the Lyman-α forest to identify voids.…”

A general framework to test gravity using galaxy clusters II: A universal model for the halo concentration in f(R) gravity

“…(e.g., Falck et al 2018;Paillas et al 2019). Models which feature Vainshtein screening have also been tested by, for example, comparing weak lensing data with SZ and X-ray cluster observations (Terukina et al 2015).…”

Weak lensing minima and peaks: Cosmological constraints and the impact of baryons

“…For example, Sánchez et al (2017) used DES redMaGiC galaxies to identify voids and found the stacked lensing signal around them to be negative at a 4σ level (also see Melchior et al 2014;Clampitt & Jain 2015;Gruen et al 2016). The lensing profile around underdense regions has also been a topic of interest for modified gravity, as dark energy is more prominent in void regions (Barreira et al 2015(Barreira et al , 2017Baker et al 2018;Paillas et al 2019). Void lensing can be more complicated than cluster lensing, as voids may have irregular shapes and the lensing signal depends on the void identification scheme.…”