The Imprint of f(R) Gravity on Non-Linear Structure Formation

TL;DR

This paper investigates how f(R) gravity modifies non-linear cosmic structures, including halo mass functions, bias, profiles, and voids, using simulations and theoretical models, revealing significant deviations from general relativity.

Contribution

It extends theoretical models of structure formation to f(R) gravity, providing accurate predictions for halo and void properties validated by simulations.

Findings

Good agreement between theory and simulations for halo mass function

Deviations in halo profiles up to 40% from GR

Significant differences in void profiles for fR0<-10^{-6}

Abstract

We test the imprint of f(R) modified gravity on the halo mass function, using N-body simulations and a theoretical model developed in (Kopp et al. 2013). We find a very good agreement between theory and simulations. We extend the theoretical model to the conditional mass function and apply it to the prediction of the linear halo bias in f(R) gravity. Using the halo model we obtain a prediction for the non-linear matter power spectrum accurate to ~10% at z=0 and up to k=2h/Mpc. We also study halo profiles for the f(R) models and find a deviation from the standard general relativity result up to 40%, depending on the halo masses and redshift. This has not been pointed out in previous analysis. Finally we study the number density and profiles of voids identified in these f(R) N-body simulations. We underline the effect of the bias and the sampling to identify voids. We find significant deviation from GR when measuring the f(R) void profiles with fR0<-10^{-6}.