Project A1


Prof. Dr. Ralf-Jürgen Dettmar
Astronomical Institute
Ruhr-University Bochum


Observational constraints on the structure and generation of magnetic fields in spiral galaxies


The strength and structure of cosmic magnetic fields on galactic scales constitute one of the
fundamental problems in modern astrophysics and they are thus in recent years subject of many
new observational and theoretical studies. To further constrain possible generation mechanisms
we propose to continue our study of the 3D magnetic field distribution in a sample of disk
galaxies using the polarized synchrotron emission at several wavelengths. The observations will
also allow us to discuss the propagation of cosmic rays in galaxies. The rotation of galactic
disks is believed to help organizing the large scale structure of the fields and the gas dynamics
is considered essential for the understanding of possible mechanisms. Therefore the magnetic
field studies are supplemented by mapping the velocity field of the ionized gas observed in the
haloes of these galaxies. The combination of these observations will help constraining possible
theoretical scenarios.