Revealing the galaxy-halo connection in IllustrisTNG

Understand

We use the IllustrisTNG (TNG) simulations to explore the galaxy-halo connection as inferred from state-of-the-art cosmological, magnetohydrodynamical simulations.

• With the high mass resolution and large volume achieved by combining the 100 Mpc (TNG100) and 300 Mpc (TNG300) volumes, we establish the mean occupancy of central and satellite galaxies and their dependence on the properties of the dark matter haloes hosting them.
• We derive best-fitting HOD parameters from TNG100 and TNG300 for target galaxy number densities of $\bar{n}_g = 0.032\,h^3$Mpc$^{-3}$ and $\bar{n}_g = 0.016\,h^3$Mpc$^{-3}$, respectively, corresponding to a minimum galaxy stellar mass of $M_\star\sim1.9\times10^9\,{\rm M}_\odot$ and $M_\star\sim3.5\times10^9\,{\rm M}_\odot$, respectively, in hosts more massive than $10^{11}\,{\rm M}_\odot$.
• Consistent with previous work, we find that haloes located in dense environments, with low concentrations, later formation times, and high angular momenta are richest in their satellite population.