Aims. We investigate the gravitational redshift in clusters of galaxies in the symmetron and Hu-Sawicky f(R) models. The characteristic feature of both models is the screening mechanism that hides the fifth force in dense environments recovering general relativity. Methods. We use N-body simulations that were run using the code \texttt{Isis}, which includes scalar fields, to analyse the deviation of observables in modified gravity models with respect to ΛCDM. Results. We find that due to the presence of the screening, the deviation is highly dependent on the halo mass. For instance, the f(R) parameters ∣fR0∣=10−5, n=1 cause an enhancement of the gravitational signal by up to 50% for halos with masses between 1013M⊙h−1 and 1014M⊙h−1. The characteristic mass range where the fifth force is most active varies with the model parameters. The usual assumption is that the presence of a fifth force leads to a deeper potential well and thus, a stronger gravitational redshift. However, we find that in cases in which only the central regions of the halos are screened, there could also be a weaker gravitational redshift.
@article{arxiv.1307.6994,
title = {Gravitational redshift profiles in the $f(R)$ and symmetron models},
author = {Max B. Gronke and Claudio Llinares and David F. Mota},
journal= {arXiv preprint arXiv:1307.6994},
year = {2014}
}