3D MHD simulations of magnetic fields and radio polarization of barred galaxies

TL;DR

This study uses 3D nonlinear MHD simulations to explore magnetic field evolution in barred galaxies, revealing configurations similar to observations and showing how bar dynamics influence magnetic structures and energy growth.

Contribution

It provides the first detailed 3D MHD simulation of magnetic fields in barred galaxies without dynamo processes, highlighting the impact of bar-driven gas flows on magnetic structures.

Findings

Magnetic field configurations resemble observed polarized intensity maps.

Magnetic arms persist longer than gaseous spiral arms.

Magnetic energy increases due to compression and shear effects.

Abstract

We present results of three-dimensional, fully nonlinear MHD simulations of a large-scale magnetic field evolution in a barred galaxy. The model does not take into consideration the dynamo process. We find that the obtained magnetic field configurations are highly similar to the observed maps of the polarized intensity of barred galaxies, because the modeled vectors form coherent structures along the bar and spiral arms. Due to the dynamical influence of the bar the gas forms spiral waves which go radially outward. Each spiral arm forms the magnetic arm which stays much longer in the disk, than the gaseous spiral structure. Additionally the modeled total energy of magnetic field grows due to strong compression and shear of non-axisymmetrical bar flows and differential rotation, respectively.