Modified-Gravity-gadget: a new code for cosmological hydrodynamical simulations of modified gravity models

Abstract

We present a 
\nnew massively parallel code for N-body and cosmological 
\nhydrodynamical simulations of modified gravity models. The code employs 
\na multigrid-accelerated Newton-Gauss-Seidel relaxation solver on an 
\nadaptive mesh to efficiently solve for perturbations in the scalar 
\ndegree of freedom of the modified gravity model. As this new algorithm 
\nis implemented as a module for the P-GADGET3 code, it can at the same 
\ntime follow the baryonic physics included in P-GADGET3, such as 
\nhydrodynamics, radiative cooling and star formation. We demonstrate that 
\nthe code works reliably by applying it to simple test problems that can 
\nbe solved analytically, as well as by comparing cosmological simulations 
\nto results from the literature. Using the new code, we perform the first 
\nnon-radiative and radiative cosmological hydrodynamical simulations of 
\nan f (R)-gravity model. We also discuss the impact of active galactic 
\nnucleus feedback on the matter power spectrum, as well as degeneracies 
\nbetween the influence of baryonic processes and modifications of 
\ngravity.