MHD simulation of galaxy formation with subgrid dynamo
Date:
The magnetic field in galaxies is one of the frontiers of galaxy formation and evolution. We perform a cosmological magnetohydrodynamic (MHD) simulation of galaxy formation with adaptive mesh refinement (AMR) techniques using RAMSES code. In this project, we manage to amplify an initially very weak seed magnetic field to a final value close to equipartition via a simple sub-grid dynamo model. The amplification process features a rapid growth in the magnetic energy, which reaches saturation at the early times of the galaxy evolution. Then the magnetic field follows the fluid distribution. We analyze the magnetic field at redshift z=0 and estimate the magnetic field strength to be a few microG within the galaxy, where turbulent motion dominates. The circumgalactic medium (CGM) is also magnetized by galactic winds driven by supernova explosions and the field strength is estimated there to be a few nG in the CGM.