Paper detail

Simulations of Galileon modified gravity: Clustering statistics in real and redshift space

We use N-body simulations to study the statistics of massive halos and redshift space distortions for theories with a standard ΛCDM expansion history and a galileon-type scalar field. The extra scalar field increases the gravitational force, leading to enhanced structure formation. We compare our measurements of the real space matter power spectrum and halo properties with fitting formula for estimating these quantities analytically. We find that a model for power spectrum, halo mass-function and halo bias, derived from ΛCDM simulations can fit the results from our simulations of modified gravity when σ_8 is appropriately adjusted. We also study the redshift space distortions in the two point correlation function measured from these simulations, finding a difference in the ratio of the redshift space to real space clustering amplitude relative to standard gravity on all scales. We find enhanced clustering on scales r>10 Mpc/h and increased damping of the correlation function for scales r<9 Mpc/h. The boost in the clustering on large scales due to the enhanced gravitational forces cannot be mimicked in a standard gravity model by simply changing σ_8. This result illustrates the usefulness of redshift space distortion measurements as a probe of modifications to General Relativity.