Stellar fraction of CL2015 (solid blue square) compared to other clusters: (a) X-ray relaxed clusters (black points) from Andreon (2012), with stellar mass of Abell 2029 updated in Renzini & Andreon (2014). The solid line is the mean model, while the shading indicates the 68% uncertainty (highest posterior density interval). The dashed corridor is the mean model ± the intrinsic scatter. (b) X-ray selected clusters (red points), after averaging in bins of eight clusters each to emphasize the mean trend while reducing the scatter around the mean relation.