Hydrodynamic Effects in the Symmetron and $f(R)$-gravity Models
  In this paper we present the first results from implementing two
scalar-tensor modified gravity theories, the symmetron and the Hu-Sawicki
$f(R)$-gravity model, into a hydrodynamic N-body code with dark matter
particles and a baryonic ideal gas. The study is a continuation of previous
work where the symmetron and $f(R)$ have been successfully implemented in the
RAMSES code, but for dark matter only. By running simulations, we show that the
deviation from $\Lambda$CDM in these models for the gas density profiles are
significantly lower than the dark matter equivalents. When it comes to the
matter power-spectrum we find that hydrodynamic simulations agree very well
with dark matter only simulations as long as we consider scales larger than
$k\sim 0.5$ h/Mpc. In general the effects of modified gravity on the baryonic
gas is found to not always mirror the effects it has on the dark matter. The
largest signature is found when considering temperature profiles. We find that
the gas temperatures in the modified gravity model studied here show
deviations, when compared to $\Lambda$CDM, that can be a factor of a few larger
than the deviations found in density profiles and power spectra.
