München 2019 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 10: Astrophysics II: Galaxies and Cosmology
EP 10.2: Talk
Friday, March 22, 2019, 11:15–11:30, HS 19
Dynamo amplification and magnetic driven outflows in disc galaxies — •Ulrich Steinwandel1,2,3, Marcus Beck3, Alexander Arth2,4, Klaus Dolag1,2, Benjamin Moster1,2, and Peter Nielaba3 — 1Universitäts-Sternwarte, München — 2Max Planck Institut für Astropyhsik, Garching — 3Universität Konstanz — 4Max Planck Institut für Extraterrestrische Physik, Garching
We carried out high resolution simulations of isolated Milky Way-like galaxies with a realistic circum galactic medium (CGM) to investigate the possibility to drive galactic outflows launched by the magnetic pressure. Our results indicate biconal (highly magnetised) outflows driven by the magnetic pressure that can reduce the mass of the galaxy by 10 per cent at the end of the simulation. Further, we investigate the amplification process of the magnetic field within our simulations. We find strong evidence for three different processes that amplify the magnetic fields in Milky Way-like galaxies. Amplification by adiabatic compression of the field lines, the alpha-omega dynamo (buoyant bubbles and large scale rotation of the disc) and the small scale turbulent dynamo (amplification by supernova induced turbulence). While adiabatic compression is dominating in the centre and the spiral arms over the whole simulation the small-scale turbulent dynamo is acting in the beginning of the simulation mostly in the inter arm regions and the centre. Once the small-scale turbulent dynamo is saturated we observe a transition towards the alpha-omega dynamo at later times leading to a non-linear growth phase of the magnetic field.