The history of mass assembly of faint red galaxies in 28 galaxy clusters since z=1.3

TL;DR

This study examines the evolution of faint red galaxies in 28 galaxy clusters from redshift 1.3 to 0, finding their abundance remains constant relative to bright red galaxies, indicating early assembly.

Contribution

It provides a comprehensive analysis over a wide redshift range, with minimized systematics, showing faint red galaxies are largely assembled by z=1.3, contrary to some previous claims.

Findings

Faint red galaxy abundance is constant from z=1.3 to 0.

No differential evolution between bright and faint red galaxies.

Faint red galaxies are largely assembled by z=1.3.

Abstract

We measure the relative evolution of the number of bright and faint (as faint as 0.05 L*) red galaxies in a sample of 28 clusters, of which 16 are at 0.50<= z<=1.27, all observed through a pair of filters bracketing the 4000 Angstrom break rest-frame. The abundance of red galaxies, relative to bright ones, is constant over all the studied redshift range, 0<z<1.3, and rules out a differential evolution between bright and faint red galaxies as large as claimed in some past works. Faint red galaxies are largely assembled and in place at z=1.3 and their deficit does not depend on cluster mass, parametrized by velocity dispersion or X-ray luminosity. Our analysis, with respect to previous one, samples a wider redshift range, minimizes systematics and put a more attention to statistical issues, keeping at the same time a large number of clusters.