Project Description
Exploring the MHD turbulence in halos of massive galaxies is very timely due to the increased sensitivity provided by the Square Kilometre Array (SKA) pathfinders (ASKAP, MeerKAT, LOFAR, and upcoming LOFAR 2.0). With the gain on sensitivity as well as survey speed, the use of Faraday grids, in addition to polarized emission for exploring magnetic field strength and topology is becoming feasible, too. Massive galaxies do not only influence large spatial volumes but also show complex and sometimes high-speed outflow patterns not observed in lower-mass galaxies.In Phase 1, we combined radio observations of edge-on galaxies with theory to study magnetic fields and MHD turbulence in galactic halos. We found that X-shaped magnetic fields following the gas outflow appear to be a common feature of late-type galaxies, and we introduced spatially varying diffusion tensors for cosmic-ray transport in galactic halos based on MHD turbulence.
In Phase 2, the radio data of the new telescopes and the MHD framework developed in Phase 1 will allow us to address the following research questions for massive galaxies:
- What is the impact of a potential instability of galactic flows out of massive galaxies on the turbulence in the halos?
- How will the multi-phase nature of the interstellar medium influence the turbulence evolution and the cosmic-ray transport in galactic halos?
- What is the effect of local sources of turbulence in galactic halos on the cosmic-ray diffusion?
