Galaxy populations in the 26 most massive galaxy clusters in the South Pole Telescope SPT-SZ survey
Monthly notices of the Royal Astronomical Society
We present a study of the optical properties of the 26 most massive galaxy clusters selected within the SPT-SZ 2500 deg^2 survey. This Sunyaev-Zel'dovich effect selected sample spans a redshift range of 0.10 < z < 1.13. We measure the galaxy radial profile, the luminosity function (LF), and the halo occupation number (HON) using optical data with a typical depth of m^* + 2. The stacked radial profiles are consistent with a NFW profile with a concentration of 2.84^+0.40_-0.37 for the red
... (RS) and 2.36^+0.38_-0.35 for the total population. Stacking the data in multiple redshift bins shows a hint of redshift evolution in the concentration when both the total population is used, and when only RS galaxies are used (at 2.1σ and 2.8σ, respectively). The stacked LF shows a faint end slope α = -1.06^+0.04_-0.03 for the total and α = -0.80^+0.04_-0.03 for the RS population. The redshift evolution of m^* is found to be consistent with a passively evolving Composite Stellar Population (CSP) model. By adopting the CSP model predictions, we explore the redshift evolution of the schechter parameters α and ϕ^*. We find α for the total population to be consistent with no evolution (0.3σ), while evidence of evolution for the red galaxies is mildly significant (1.1-2.1σ). The data show that the density ϕ^*/E^2(z) decreases with redshift, in tension with the self-similar expectation at a 2.4σ level for the total population. The measured HON-mass relation has a lower normalization than previous studies at low redshift. Finally, our data support HON redshift evolution at a 2.1σ level, with clusters at higher redshift containing fewer galaxies per unit mass to m^* + 3 than their low-z counterparts [abridged].