# Density profiles and voids in modified gravity models

## TL;DR

This paper investigates how voids and halo properties in the universe can reveal differences in gravity strength on large scales, offering new ways to test modified gravity models beyond traditional methods.

## Contribution

It demonstrates that void and halo density profiles, along with their abundances, can serve as complementary probes to constrain modified gravity models, highlighting effects on large-scale structure formation.

## Key findings

- Weaker large-scale gravity models have fewer large voids and massive halos.
- Stronger gravity leads to more concentrated halos and thinner void walls.
- Void and halo profiles provide additional constraints on gravity models.

## Abstract

We study the formation of voids in a modified gravity model in which gravity is generically stronger or weaker on large scales. We show that void abundances provide complementary information to halo abundances: if normalized to the CMB, models with weaker large-scale gravity have smaller large scale power, fewer massive halos and fewer large voids, although the scalings are not completely degenerate with $\sigma_8$. Our results suggest that, in addition to their abundances, halo and void density profiles may also provide interesting constraints on such models: stronger large scale gravity produces more concentrated halos, and thinner void walls. This potentially affects the scaling relations commonly assumed to translate cluster observables to halo masses, potentially making these too, useful probes of gravity.