Searching for Correlations between Satellite Galaxy Populations and the Cold Circumgalactic Medium around TNG50 Galaxies

Abstract We investigate the impact of satellites, a potentially important contributor toward the cold gas assembly of a halo, on the cold gas budgets of 197 TNG50 simulated halos with masses of 10 10.85 ≤ M 200 c / M ⊙ ≤ 10 12.24 at z = 0. To highlight the effect of satellites, we split the sample into three mass bins. We find that the total number of satellites, total mass of satellites, number of massive satellites, and stellar mass of the most massive satellite all correlate with the cold gas mass in halos. The total number of satellites (stellar mass of the most massive satellite) correlates the most with the halo cold gas mass for low (middle) mass halos. The number of massive or observable satellites correlates with cold gas mass in a similar manner as the total number of satellites. Our findings can, therefore, be used to guide future observers to focus on the link between the number of observable satellites and the amount of cold gas in a halo. Despite this correlation, we find that much of the cold gas lies far from the satellites. This leads us to conclude that satellites are unlikely to be the main supplier for cold gas in halos. However, we discuss how they may act in tandem with other sources, such that the satellite population correlates with the total cold gas in their host halo.