Figure 1

The three IllustrisTNG simulation volumes: TNG50, TNG100, and TNG300. In each case the name denotes the box side-length in comoving Mpc, and all three are shown in projected dark matter density. The largest, TNG300, enables the study of rare, massive objects such as galaxy clusters, and provides unparalleled statistics of the galaxy population as a whole. TNG50, with a mass resolution more than one hundred times better, provides for the detailed examination of internal, structural properties and small-scale phenomena. In the middle, TNG100 uses the same initial conditions as the original Illustris simulation, providing a useful balance of resolution and volume for studying many aspects of galaxy evolution