Center for Magnetic Self Organization

in Laboratory and Astrophysical Plasmas

Magnetic field amplification in galaxy clusters

Galaxy clusters are observed to be pervaded by hot, tenuous gas, which is strongly magnetized. While some of this gas was apparently stripped from galaxies, much of it is primordial, and simple estimates show that the magnetic field is too strong to simply have been torn from galaxies with their interstellar gas further amplification is required. We have performed state of the art cosmological magnetohydrodynamic simulations, with adaptive mesh refinement to show that magnetic fields injected by active galaxies can be amplified by intracluster medium turbulence through a small scale dynamo process. Such turbulence is generated and sustained by mergers of galaxies or groups of galaxies with the cluster.

Distribution of magnetic fieldstrengths in a turbulent galaxy cluster simulation. Strong filaments are embedded within the weaker turbulent field. The range of fieldstrengths is similar to what is observed.

A National Science Foundation Physics Frontier Center,
established in coordination with the Department of Energy.