Modified Gravity-GADGET: A new code for cosmological hydrodynamical
  simulations of modified gravity models
  We present a new massively parallel code for N-body and cosmological
hydrodynamical simulations of modified gravity models. The code employs a
multigrid-accelerated Newton-Gauss-Seidel relaxation solver on an adaptive mesh
to efficiently solve for perturbations in the scalar degree of freedom of the
modified gravity model. As this new algorithm is implemented as a module for
the P-Gadget3 code, it can at the same time follow the baryonic physics
included in P-Gadget3, such as hydrodynamics, radiative cooling and star
formation. We demonstrate that the code works reliably by applying it to simple
test problems that can be solved analytically, as well as by comparing
cosmological simulations to results from the literature. Using the new code, we
perform the first non-radiative and radiative cosmological hydrodynamical
simulations of an f(R)-gravity model. We also discuss the impact of AGN
feedback on the matter power spectrum, as well as degeneracies between the
influence of baryonic processes and modifications of gravity.
