Abstract

Contributed Talk - Splinter StarFormation

Toward modeling the multi-phase ISM in a cosmological context

Rainer Weinberger
Leibniz-Institut für Astrophysik Potsdam (AIP)

Cosmological hydrodynamical simulations have significantly advanced our understanding of galaxy formation. However, these simulations often rely on simple models of the interstellar medium (ISM), which can limit their predictive power. In practice, many simulations apply a small-scale closure via effective equation of state. This leads to the formation of stable star-forming gas disks without the need to spatially resolve their multi-phase nature, but creates problems when accurately model the connection between gas disks and galactic outflows. This limitation restricts the predictive power of such simulations, and makes it difficult to compare results directly with observational data. To address these challenges, we introduce a multi-fluid hydrodynamics approach for modeling the ISM. Unlike traditional methods, this technique is capable of capturing multiple gas phases within galaxies without spatially resolving them. Additionally, it incorporates small-scale effects as source or interaction terms in the equations, providing a mathematically better defined small-scale closure. We present an illustrative example focused on a galactic outflow driven by star formation to demonstrate the advantages of our method. Finally, we discuss future directions for cosmological simulations and potential avenues for improving the reliability and predictive accuracy of their results.