EDP Sciences
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Volume 402, Number 3, May II 2003
First Science with the ODIN satellite
Page(s) 879 - 889
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20021666

A&A 402, 879-889 (2003)
DOI: 10.1051/0004-6361:20021666

Magnetic field evolution in galaxies interacting with the intracluster medium

3D numerical simulations
K. Otmianowska-Mazur1 and B. Vollmer2

1  Astronomical Observatory Jagiellonian University Kraków, Poland
2  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

(Received 31 October 2002 / Accepted 27 January 2003 )

A fully three-dimensional (3D) magnetohydrodynamical (MHD) model is applied to simulate the evolution of the large-scale magnetic field in cluster galaxies interacting with the intra-cluster medium (ICM). As the model input we use time-dependent gas velocity fields resulting from 3D N-body sticky-particle simulations of a galaxy. The modeled clouds are affected by the ram pressure due to their rapid motion through the ICM in the central part of a cluster. Numerical simulations have shown that after the initial compression phase due to ram pressure, a process of gas re-accretion onto the galactic disk takes place. We find that the gas re-accretion leads to an increase of the total magnetic energy without any dynamo action. The simulated magnetic fields are used to construct the model maps of high-frequency (Faraday rotation-free) polarized radio emission. We show that the evolution of the polarized intensity shows features that are characteristic of different evolutionary stages of an ICM-ISM interaction. The comparison of polarized radio continuum emission maps with our model permits us to determine whether the galaxy is in the compression or in the re-accretion phase. It also provides an important constraint upon the dynamical modeling of ICM-ISM interactions.

Key words: galaxies: evolution -- galaxies: ISM -- galaxies: magnetic fields -- galaxies: clusters: general -- galaxies: intergalactic medium -- methods: numerical

Offprint request: K. Otmianowska-Mazur, otmian@oa.uj.edu.pl

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