Magnetic fields and radio polarization of barred galaxies
Authors: Otmianowska-Mazur, K.; Elstner, D.
Source: Astrophysics and Space Science, Volume 284, Number 2, 2003 , pp. 761-764(4)
In order to simulate evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo we apply a three-dimensional (3D) MHD numerical model. We solve a induction equation using a time-dependent velocity field of molecular gas resulting from self-consistent 3D N-body simulations of a galactic disk. The gaseous halo rotates differentially co-rotating with the disk. In our model we introduce the dynamo process causing the amplification of the magnetic field as well as the formation of field structures high above the galactic disk. The simulated magnetic fields are used to construct the models of a high-frequency (Faraday rotation-free) polarized radio emission that accounts for effects of projection and limited resolution, and is thus suitable for direct comparison with observations. We found that the resultant magnetic field correctly reproduces the observed structures of polarization B-vectors, forming coherent patterns well aligned with spiral arms and with the bar. The process initializing a wave-like behavior of the magnetic field, which efficiently forms magnetic maxima between the spiral arms, is demonstrated.
Document Type: Research Article
Affiliations: Astronomical Observatory Jagiellonian University, Kraków, Poland Astrophysikalishes Institut Potsdam, Germany
Publication date: 2003-01-01