Non-linear dynamics of the minimal theory of massive gravity

TL;DR

This paper explores the cosmological implications of the minimal theory of massive gravity (MTMG) by simulating its effects on structure formation, revealing subtle deviations from general relativity, especially in void densities and halo abundances.

Contribution

The study introduces an environment-dependent effective gravitational constant in N-body simulations of MTMG and identifies key observational signatures distinguishing it from GR.

Findings

Void densities are higher in MTMG than in GR.

MTMG predicts more massive halos and fewer small halos.

Deviations from GR are small in halo profiles and power spectra.

Abstract

We investigate cosmological signatures of the minimal theory of massive gravity (MTMG). To this aim, we simulate the normal branch of the MTMG by employing the \textsc{Ramses} \mbox{$N$-body} code and extending it with an effective gravitational constant $G_{\rm eff}$. We implement an environment-dependent $G_{\rm eff}$ as a function of the graviton mass and the local energy density as predicted by MTMG. We find that halo density profiles are not a good probe for MTMG, because deviations from general relativity (GR) are quite small. Similarly, the matter power spectra show deviations only at the percentage level. However, we find a clear difference between MTMG and GR in that voids are denser in MTMG than in GR. As measuring void profiles is quite a complex task from an observational point of view, a better probe of MTMG would be the halo abundances. In this case, MTMG creates a larger amount of massive halos, while there is a suppression in the abundance of small halos.