Atomic and molecular gas in IllustrisTNG galaxies at low redshift

Understand

We have recently developed a post-processing framework to estimate the abundance of atomic and molecular hydrogen (HI and H2, respectively) in galaxies in large-volume cosmological simulations.

• Here we compare the HI and H2 content of IllustrisTNG galaxies to observations.
• We mostly restrict this comparison to $z \approx 0$ and consider six observational metrics: the overall abundance of HI and H2, their mass functions, gas fractions as a function of stellar mass, the correlation between H2 and star formation rate, the spatial distribution of gas, and the correlation between gas content and morphology.
• We find generally good agreement between simulations and observations, particularly for the gas fractions and the HI mass-size relation.