Evidence for Significant Growth in the Stellar Mass of Brightest Cluster
  Galaxies over the Past 10 Billion Years
  Using new and published data, we construct a sample of 160 brightest cluster
galaxies (BCGs) spanning the redshift interval 0.03 < z < 1.63. We use this
sample, which covers 70% of the history of the universe, to measure the growth
in the stellar mass of BCGs after correcting for the correlation between the
stellar mass of the BCG and the mass of the cluster in which it lives. We find
that the stellar mass of BCGs increase by a factor of 1.8 between z=0.9 and
z=0.2. Compared to earlier works, our result is closer to the predictions of
semi-analytic models. However, BCGs at z=0.9, relative to BCGs at z=0.2, are
still a factor of 1.5 more massive than the predictions of these models. Star
formation rates in BCGs at z~1 are generally to low to result in significant
amounts of mass. Instead, it is likely that most of the mass build up occurs
through mainly dry mergers in which perhaps half of the mass is lost to the
intra-cluster medium of the cluster.
