Galaxies and the gas surrounding them are turbulent and multiphase, i.e., colder (< 10^4 K) gas is embedded in a much larger, volume filling hot (≳ 10^6 K) phase, and regulates the fuel supply for star formation and black hole growth.
These properties are fundamentally linked with the multiscale nature of the problem which poses serious challenges for simulations in the field and implies that all galactic simulations are unconverged.
This implies that many ‘predictions’ of such simulations are in fact resolution dependent and will change with increasing computing power.
Similarly, the common practice to rule out physical models based on the comparison of (unconverged!) simulation output with observed quantities is at least questionable.
To overcome this challenge, and to find solid ground from which we can build upon, we propose to run the biggest simulation of turbulent, multiphase gas ever performed. This will literally allow us to resolve the challenges by being able to simulate the full range of physical length scales and find the – converged – cold gas structure.
The outcome of the proposed research will inform future larger scale simulations and will open the door to a meaningful comparison of such simulations to observations.