SILCC VII - Gas kinematics and multiphase outflows of the simulated ISM at high gas surface densities
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Movie: The evolution of the multiphase interstellar medium (ISM) modelled with a magnetohydrodynamics (MHD) simulation of a stratified gas disk and initial gas surface density of Σgas = 100 M⊙ pc2. The simulation includes all major ISM processes and stellar feedback in the form of type II supernovae, stellar winds, ionising UV radiation, as well as acceleration and anisotropic diffusion of cosmic rays (CRs). Shown are the edge-on (top row) and face-on (bottom row) views of the total gas column density, mass-weighted temperature, ionised, atomic, and molecular hydrogen column densities, and the density-weighted magnetic field strength and cosmic ray energy density (from left to right). Individual HII regions (3rd panel) from active star clusters are visible. The star-forming galactic ISM is concentrated around the midplane. Grey circles in the 1st and 3rd panels indicate star clusters with different masses. Translucent symbols indicate old star clusters with no active massive stars in them. Stellar feedback generates a highly structured and turbulent multiphase ISM with all its major thermal and non-thermal components. Strong galactic outflows with mass loading factors above unity are driven by the hot gas phase (T > 3 × 105 K) and additionally supported by an long-lived CR pressure gradient.
Figure 1: This plot shows the velocity dispersion (y-axis) as a function of the star formation rate (x-axis) for the warm-ionised medium (WIM, ∼10.000 K, orange squares) and the cold neutral medium (CNM, ∼300 K, blue squares). The models with different initial conditions are indicated by different symbols. Overall, the simulations follow the observed trends (Leroy et al. 2008, data points with black boxes) very well. The velocity dispersion increases with star formation rate and the warm gas motions become supersonic.
Theoretical Astrophysics group Cologne - TAC
Our research deals with the numerical modelling of the star formation process by means of high-performance, 3D, magneto-hydrodynamical (MHD) simulations. The simulations cover large spatial scales from ISM physics on kpc scales over molecular clouds on scales of 10 - 100 pc to star forming filaments on (sub-) pc scales and finally to protostellar discs and jets on scales of 10 - 1000 AU.
In our research group we use several tools like the (M)HD codes FLASH, GADGET, GANDALF, the astrochemical code KROME, 3D-PDR or radiative transport codes like RADMC-3D and POLARIS.
Prof. Dr. Stefanie Walch-Gassner is the head of the SILCC project (SImulating the life Cyle of molecular Clouds), a collaboration of several European astrophysical institutes, which has set the aim to model the formation, evolution, and dispersal of molecular clouds in 3D, MHD simulations with particular focus on a detailed astro-chemical modelling and the inclusion of various feedback processes.
