An MHD Gadget for cosmological simulations

TL;DR

This paper introduces an MHD extension to the GADGET cosmological simulation code, enabling detailed studies of magnetic fields in galaxy clusters and their impact on structure formation, validated through various tests and applications.

Contribution

The paper presents the implementation of magneto hydrodynamics in the GADGET SPH code, including stability schemes and validation against ATHENA, advancing cosmological magnetic field simulations.

Findings

SPH MHD code shows excellent agreement with ATHENA.

Magnetic field profiles in galaxy clusters are robust and consistent with previous studies.

The implementation is suitable for realistic cosmological simulations.

Abstract

Various radio observations have showed that the hot atmospheres of galaxy clusters are magnetized. However, our understanding of the origin of these magnetic fields, their implications on structure formation and their interplay with the dynamics of the cluster atmosphere, especially in the centers of galaxy clusters is still very limited. In preparation to the upcoming new generation of radio telescopes (like EVLA, LWA, LOFAR and SKA), a huge effort is being made to learn more about cosmological magnetic fields from the observational perspective. Here we present the implementation of magneto hydrodynamics in the cosmological SPH code GADGET. We discuss the details of the implementation and various schemes to suppress numerical instabilities as well as regularization schemes, in the context of cosmological simulations. The performance of the SPH MHD code is demonstrated in various one and two dimensional test problems, which we performed if a fully, three dimensional setup to test the code under realistic circumstances. Comparing with solutions obtained with ATHENA, we find excellent agreement with our SPH MHD implementation. Finally we apply our SPH MHD implementation to forming galaxy clusters within a large, cosmological box. Performing a resolution study we demonstrate the robustness of the predicted shape of the magnetic field profiles in galaxy clusters, which is in good agreement with previous studies.