Universe Cluster Seminar: The Interstellar Medium: confronting 3D high resolution simulations with observations

by Dieter Breitschwerdt (TU Berlin)

Tuesday 11 Oct 2011, 11:00 → 12:30 Europe/Berlin

lecture hall 1.18.b (MPE, Garching)

The evolution of late type galaxies is driven by the continuous formation of stars out of interstellar matter (ISM). The ISM is a highly compressible and magnetized medium, characterized by large Reynolds numbers. It is energized mainly by Supernova (SN) explosions and stellar winds of massive stars. As a result, shear flows generate a high level of vorticity, leading to a very turbulent medium. The inherent complexity and nonlinearity of the system require a careful approach, especially for advanced numerical 3D parallel computer simulations. We have built a bottom-up model of a turbulent SN driven ISM over the years, showing (amongst others) by large scale hydro- and magnetohydrodynamical simulations (i) the existence of a large scale galactic fountain, (ii) a reduced volume filling factor of hot gas, and (iii) a considerable fraction of the gas mass residing in classical thermally unstable phases, (iv) that the warm ionized medium has a lognormal distribution. In addition, we have recently calculated the fully time-dependent ionization structure for the 10 most abundant elements along with the hydrodynamics. Since the plasma is generally out of ionization equilibrium, the cooling function is varying both in space and time, depending on the thermal history of the plasma. As a special patch of ISM, the evolution of the local superbubble, in which our solar system is embedded, will be discussed. The simulations are compared to some recent observations, and prospects of current and future work are discussed.

Slides Universe_Cluster_Breitschwerdt.pdf