The Massive and Distant Clusters of WISE Survey. XI. Stellar Mass Fractions and Luminosity Functions of MaDCoWS Clusters at z ∼ 1

We present stellar mass fractions and composite luminosity functions (LFs) for a sample of 12 clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) in the redshift range 0.951 <= z <= 1.43. Using spectral energy distribution fitting of optical and deep mid-infrared photometry, we establish the membership of objects along the lines of sight to these clusters and calculate the stellar masses of member galaxies. This allows us to calculate the stellar mass of the clusters much more precisely than in previous works. We find stellar mass fractions for these clusters largely consistent with previous works, and an apparent negative correlation with total cluster mass. We measure a composite 3.6 mu m LF down to m* + 2.5 for all 12 clusters. Fitting a Schechter function to the LF, we find a characteristic 3.6 mu m magnitude of m* = 19.83 +/- 0.12 and faint-end slope of alpha = -0.81 +/- 0.10 for the full sample at a mean redshift of (z) over bar = 1.18. We also divide the clusters into high- and low-redshift bins at (z) over bar = 1.29 and (z) over bar = 1.06, respectively, and measure a composite LF for each bin. We see a small, but statistically significant, evolution in m* and alpha-consistent with passive evolution-when we study the joint fit to the two parameters, which is probing the evolution of faint cluster galaxies at z similar to 1. This highlights the importance of deep IR data in studying the evolution of cluster galaxy populations at high redshift.