Red-sequence early-type galaxies in clusters

We carried out a photometric and structural analysis in the rest-frame V band of a mass-selected (logM/M_{sun}_>10.7) sample of red sequence galaxies in 14 galaxy clusters, six of which are at z>1.45, namely JKCS041, IDCS J1426.5+3508, SpARCS104922.6+564032.5, SpARCSJ022426-032330, XDCPJ0044.0-2033, and SPT-CLJ2040-4451. To this aim, we reduced/analysed about 300 orbits of multicolor images taken with the Advanced Camera for Survey and the Wide Field Camera 3 on Hubble Space Telescope.

We uniformly morphologically classified galaxies from z=0.023 to z=1.803, and we homogeneously derived sizes (effective radii) for the entire sample. Furthermore, our size derivation allows, and therefore is not biased by, the presence of the usual variety of morphological structures seen in early-type galaxies, such as bulges, bars, disks, isophote twists, and ellipticity gradients. By such a mass-selected sample, composed of 244 red-sequence early-type galaxies, we find that the log of the galaxy size at a fixed stellar mass, logM/M_{sun}_=11 increases with time with a rate of 0.023+/-0.002dex per Gyr in the last 10Gyr, in marked contrast with the threefold increase found in literature for galaxies in the general field over the same period.