3D simulations of magnetic fields in barred galaxies

Abstract

In the present project we apply a 3D MHD numerical model to simulate the evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo. A time-dependent velocity field of molecular gas resulting fromself-consistent 3D N-body simulations of a galactic diskis used to solve the induction equation. Thegaseous halo rotates differentially, co-rotating with the disk.In order to form field structures high above the galactic diskin our model, we introduce the dynamo process causing, as well, theamplification of the magnetic field. The simulated magnetic fieldsare used to construct the maps of a high-frequency (Faraday rotation-free)polarized radio emission that accounts for effects of projectionand limited resolution, and is thussuitable for direct comparison with observations. The magnetic field obtained correctly reproduces the observed structures of polarization B-vectors. They formcoherent patterns well aligned with spiral arms and with the bar. We found the dynamical process which initializes a wave-like behavior of the magnetic fieldefficiently forming magnetic maxima between the spiral arms. The magnetic structuresin a form of flux tubes extending along the spiral arms are found, as well.