1999/06/21 by Klaus Dolag, Dolag, Klaus, Matthias Bartelmann +4 · 4 citations
Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Scientific Research and Discoveries #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9906329
accepted by Astronomy & Astrophysics
arxiv created 1999/06/21 · openalex publication_date 1999/06/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction, and smooth-particle hydrodynamics for the gas component. We employ the usual MHD equations for the evolution of the magnetic field in an ideally conducting plasma. As a first application, we focus on the question what kind of initial magnetic fields yield final field configurations within clusters which are compatible with Faraday-rotation measurements. Our main results can be summarised as follows: (i) Initial magnetic field strengths are amplified by approximately three orders of magnitude in cluster cores, one order of magnitude above the expectation from spherical collapse. (ii) Vastly different initial field configurations (homogeneous or chaotic) yield results that cannot significantly be distinguished. (iii) Micro-Gauss fields and Faraday-rotation observations are well reproduced in our simulations starting from initial magnetic fields of \~ 10-9 G strength at redshift 15. Our results show that (i) shear flows in clusters are crucial for amplifying magnetic fields beyond simple compression, (ii) final field configurations in clusters are dominated by the cluster collapse rather than by the initial configuration, and (iii) initial magnetic fields of order 10-9 G are required to match Faraday-rotation observations in real clusters.