Astrophysical Turbulence

Simulations of interacting disk galaxies

disk galaxy

Disk galaxies are arguably the most complex objects in astrophysics.


They are composed of dark matter, gas, and stars. The physics involves gravity, turbulent gas dynamics, heating and cooling, and magnetic fields. In contrast to the size of a typical disk galaxy, which is of the order of 10 kpc, many important processes operate on much smaller scales. Examples are cooling instabilties, magnetic dynamo action, and star formation in interstellar clouds. Moreover, galaxies exchange gas with the surrounding intergalactic medium and interact with other galaxies in close encounters and mergers.

 

Even with the largest available supercomputers, exact computations are infeasible. For this reason, we need subgrid scale models to approximate processes on scales smaller than the grid resolution in numerical simulations.

 

An ongoing PhD project funded by the DFG aims at numerical simulations of star bursts and magnetic field amplification in merging disk galaxies with the Enzo code. The project is based on the preliminary work of Rodenbeck & Schleicher (2016). Key challanges are the combination of disk galaxy models with fully dynamical dark matter halos and the application of a new MHD subgrid scale model (Grete et al. 2016).