ALHAMBRA survey galaxy clusters and groups

Cluster redshifts are expected to be recovered with ~0.6 percent precision for z<1. We also expect to measure cluster masses with sigma_Mh_|M*CL_~0.25-0.35dex precision down to ~3x10^13^M_{sun}_, masses which are 50 percent smaller than those reached by similar work. We have compared these detections with previous optical, spectroscopic and X-rays work, finding an excellent agreement with the rates reported from the simulations.

We have also explored the overall properties of these detections such as the presence of a colour-magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z<0.5).