Pre-lunch talk by Dylan Nelson – University of Copenhagen

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Pre-lunch talk by Dylan Nelson

Dylan Nelson (Harvard)


How galaxies acquire their gas: perspectives from hydrodynamical simulations


Despite significant progress with numerical simulations over the past decade, the process by which galaxies acquire their baryonic matter through cosmic time remains poorly understood. I will discuss two of our recent efforts to examine this question using cosmological hydrodynamical simulations run with the moving-mesh code Arepo. First, I will contrast our results to earlier simulations which identified 'cold flows' or 'cold mode accretion' as a primary driver of galaxy growth, where we find significant differences in the thermodynamic history of accreting gas. Then, I will present some ongoing work -- a suite of single object, high-resolution "zooms" which aim to better resolve the gas-dynamics of the circumgalactic regime. We study the interaction between filamentary inflow from the IGM and the quasi-static hot halo atmosphere, the existence of a strong virial shock, and consider implications of the angular variability (i.e., lack of spherical symmetry) in the structure of halo gas.