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

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, out of which 16 are at  0.50 ≤ z ≤ 1.27  , all observed through a pair of filters bracketing the 4000-Å 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 abundance does not depend on cluster mass, parametrized by velocity dispersion or X-ray luminosity. Our analysis, with respect to the 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.