Gravitational redshift profiles in the $f(R)$ and symmetron models
  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 $\Lambda$CDM. 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 $|f_{R0}|=10^{-5}$, $n=1$ cause an enhancement of the
gravitational signal by up to 50% for halos with masses between
$10^{13}\,M_\odot h^{-1}$ and $10^{14}\,M_\odot h^{-1}$. 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.
