RedMaPPer: Evolution and Mass Dependence of the Conditional Luminosity Functions of Red Galaxies in Galaxy Clusters

TL;DR

This paper analyzes the luminosity distribution and evolution of red galaxies in galaxy clusters, proposing a model linking galaxy luminosity to halo mass and examining redshift evolution and central galaxy properties.

Contribution

It introduces a simple model for galaxy luminosity-halo mass relation, fitted to a large SDSS cluster sample, and explores the evolution and correlation of galaxy luminosities with cluster properties.

Findings

Central galaxy luminosity scales with halo mass as log L ∝ 0.39 log M.

Scatter in central galaxy luminosity at fixed mass is about 0.23 dex.

Satellite luminosities dim by ~20% from z=0.3 to z=0.1.

Abstract

We characterize the luminosity distribution, halo mass dependence, and redshift evolution of red galaxies in galaxy clusters using the SDSS Data Release 8 RedMaPPer cluster sample. We propose a simple prescription for the relationship between the luminosity of both central and satellite galaxies and the mass of their host halos, and show that this model is well-fit by the data. Using a larger galaxy cluster sample than previously employed in the literature, we find that the luminosities of central galaxies scale as $\langle \log L \rangle \propto A_L \log (M_{200b})$, with $A_L=0.39\pm0.04$, and that the scatter of the central--galaxy luminosity at fixed $M_{200b}$ ( $\sigma_{\log L|M}$) is $0.23 ^{+0.05}_{-0.04}$ dex, with the error bar including systematics due to miscentering of the cluster finder, photometry, and photometric redshift estimation. Our data prefers a positive correlation between the luminosity of central galaxies and the observed richness of clusters at a fixed halo mass, with an effective correlation coefficient $d_{\rm{eff}}=0.36^{+0.17}_{-0.16}$. The characteristic luminosity of satellites becomes dimmer from $z=0.3$ to $z=0.1$ by $\sim 20\%$ after accounting for passive evolution. We estimate the fraction of galaxy clusters where the brightest galaxy is not the central to be $P_{\rm{BNC}} \sim 20\%$. We discuss implications of these findings in the context of galaxy evolution and the galaxy--halo connection.