Modified Gravity-GADGET: A new code for cosmological hydrodynamical simulations of modified gravity models

TL;DR

This paper introduces a new parallel simulation code that combines modified gravity models with baryonic physics, enabling detailed cosmological studies of structure formation under alternative gravity theories.

Contribution

The paper presents a novel, efficient code integrating modified gravity simulations with baryonic physics, including hydrodynamics and star formation, within the P-Gadget3 framework.

Findings

Successfully tested the code with analytical and literature benchmarks.

Performed first non-radiative and radiative hydrodynamical simulations of f(R)-gravity.

Analyzed the effects of AGN feedback and baryonic processes on the matter power spectrum.

Abstract

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.