Atomic gas in galaxies: a critical test for state-of-the-art cosmological simulations of galaxy formation

Numerical cosmological hydrodynamical simulations are nowadays a major tool for understanding the formation and evolution of galaxies. These simulations contain a number of so-called sub-grid prescriptions, which are calibrated through a comparison of the simulated galaxy population to the galaxy population observed in the nearby Universe. In order to directly test the galaxy formation model, it is necessary to make a comparison based on properties that are not directly involved in this calibration process. The atomic hydrogen (HI) gas, an important component in the interstellar medium of galaxies, is ideal for these purposes.

The objective of this project is to critically test the TNG50 simulation, probably the most advanced cosmological hydrodynamical simulation of its kind today, via its HI properties. We will develop an self-consistent post-processing method to simulate mock HI observations, and we will apply this recipe to calculate HI properties of galaxies from the TNG50 simulation. Finally, we will compare the HI properties of the simulated TNG50 galaxies to existing and upcoming HI surveys. In particular, we will use new observational results from the multi-wavelength DustPedia project and the ongoing MeerKAT MHONGOOSE survey as powerful benchmarks to test the model.