The Massive and Distant Clusters of WISE Survey XI: Stellar Mass Fractions and Luminosity Functions of MaDCoWS Clusters at $z \sim 1$

TL;DR

This paper analyzes stellar mass fractions and luminosity functions of high-redshift galaxy clusters from the MaDCoWS survey, revealing their consistency with previous findings and evidence of passive evolution of faint galaxies at z~1.

Contribution

It provides new measurements of stellar mass fractions and luminosity functions for MaDCoWS clusters at z~1, including evolution analysis of faint galaxy populations.

Findings

Stellar mass fractions are consistent with prior studies.

Measured luminosity function parameters at z~1.

Detected statistically significant evolution in LF parameters.

Abstract

We present stellar mass fractions and composite luminosity functions (LFs) for a sample of \Ncl\ clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) at a redshift range of $0.951 \leq z \leq 1.43$. Using SED 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. We find stellar mass fractions for these clusters largely consistent with previous works, including appearing to display a negative correlation with total cluster mass. We measure a composite $3.6~\mathrm{\mu m}$ LF down to $m^*+2.5$ for all 12 clusters. Fitting a Schechter function to the LF, we find a characteristic $3.6~\mathrm{\mu m}$ magnitude of $m^*=19.83\pm0.12$ and faint-end slope of $\alpha=-0.81\pm0.10$ for the full sample at a mean redshift of $\bar{z} = 1.18$. We also divide the clusters into high- and low-redshift bins at $\bar{z}=1.29$ and $\bar{z}=1.06$ 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 $z\sim1$. This highlights the importance of deep IR data in studying the evolution of cluster galaxy populations at high-redshift.