Connecting galaxy evolution in clusters with their radial profiles and
  phase space distribution: results from the IllustrisTNG hydrodynamical
  simulations
  We study the population of galaxies around galaxy clusters in the
hydrodynamic simulation suite IllustrisTNG 300-1 to study the signatures of
their evolutionary history on observable properties. We measure the radial
number density profile, phase space distribution, and splashback radius for
galaxies of different masses and colors over the redshift range $z=0-1$. The
three primary physical effects which shape the galaxy distribution within
clusters are the galaxy quenching, angular momentum distribution and dynamical
friction. We find three distinct populations of galaxies by applying a Gaussian
mixture model to their distribution in color and mass. They have distinct
evolutionary histories and leave distinct signatures on their distribution
around cluster halos. We find that low-mass red galaxies show the most
concentrated distribution in clusters and the largest splashback radius, while
high-mass red galaxies show a less concentrated distribution and a smaller
splashback radius. Blue galaxies, which mostly quench into the low-mass red
population, have the shallowest distribution within the clusters, with those on
radial orbits quenched rapidly before reaching pericenter. Comparison with the
distribution of galaxies from the Dark Energy Survey (DES) survey around
Sunyaev-Zeldovich (SZ) clusters from the Atacama Cosmology Telescope (ACT) and
South Pole Telescope (SPT) surveys shows evidence for differences in galaxy
evolution between simulations and data.
