Modelling turbulent effects of stellar feedback in cosmological simulations
by Jan Frederik Engels
Date of Examination:2017-10-23
Date of issue:2017-10-30
Advisor:Prof. Dr. Jens Niemeyer
Referee:Prof. Dr. Jens Niemeyer
Referee:Prof. Dr. Ansgar Reiners
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Abstract
English
In order to study the influence of turbulence on star formation, stellar feedback, and the mixing of metals into the circumgalactic medium (CGM), we implemented a model for star formation and stellar feedback and employ it in cosmological large eddy simulations using a subgrid scale turbulence model (SGS). We find that the pure SGS model significantly decreases star formation and increases the efficiency of feedback, leading to much stronger outflows. We show that these effects can not be mimicked by cooling suppression and study explicit turbulent feedback, which does not affect diagnostics like star formation rates (SFR) or outflow radii significantly. Finally, we show that turbulent diffusion of metals does not lead to a higher enrichment in the CGM, while turbulent diffusion of internal energy reverts most of the effects introduced by switching on the SGS model and leads to a simulation almost indistinguishable from one without the SGS model in SFR or (stacked) halo profiles.
Keywords: cosmological simulations, hydrodynamics, turbulence, circumgalactic medium, numerical modelling