the BCG’s mass growth at $z\geq2$, while multiple dry mergers of smaller galaxies dominate the mass assembly at $z\leq1$ [e.g. @DeLucia2007; @Naab2009; @Laporte2013]. The simulations, however, differ in the stellar mass growth they predict for BCGs. For example, [@DeLucia2007] find that BCGs have changed their mass by a factor of 4 from $z = 1 - 0$, mainly through minor[^2] mergers. [@Laporte2013] on the other hand predict a BCG mass growth factor closer to 2 over the same redshift range, however this model finds that both major[^3] and minor mergers contribute significantly towards the mass growth of these massive galaxies.

The discrepancies between the BCGs’ observed stellar mass growth and that predicted by simulations are quite apparent. This may be because mergers do not contribute significantly to the stellar mass growth of the BCGs if a significant fraction of the merging mass ends up in the cluster’s intracluster light (ICL). The ICL can be described as stars that are not gravitationally bound to any single galaxy, but rather to the cluster potential. Although the origin of the ICL is not known, it is thought that tidal stripping of satellite galaxies and merger events (involving BCGs) contribute towards the stellar mass 