Bright Central Galaxies (BCGs) in Dark Energy Survey Science Verification Data: Stellar Mass Growth in X-Ray Selected Clusters and Groups Since z=1.2

We study the stellar mass of bright central galaxies and its evolution with time. We use a new sample of 106 $00.9$, we confirm previous findings that the observed BCGs appear to be overly-massive (luminous) when compared to the models. The growth rate for BCGs in a $M_{200}= 10^{13.8}$ solar mass cluster at z=1.0 is observed to be slower than that predicted by hierarchical growth and semi-analytic modeling.