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Paper: Does the Development of Galactic Magnetic Fields Need a Large Gaseous Halo?
Volume: 165, The Third Stromlo Symposium: The Galactic Halo
Page: 498
Authors: Otmianowska-Mazur, Katarzyna; von Linden, Susanne; Elstner, Detlef; Soida, Marian
Abstract: A fully three-dimensional (3D) MHD model is applied to simulate the evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo extended from 0.8~kpc to 2.8~kpc above the galactic plane. As the model input we use a time dependent velocity field of a molecular gas resulting from self-consistent 3D N-body simulations of a galactic disk. We assume that the gaseous halo rotates differentially co-rotating with the disk (Kalberla & Kerp, 1998). A dynamo process included in the model yields 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 models of a high-frequency (Faraday rotation-free) polarized radio emission accounted for effects of projection and limited resolution, thus suitable for direct comparisons 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 inclusion of the galactic halo constitutes a important step towards the realistic model of galactic magnetic fields including as many as possible dynamical components.
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