  Understanding the formation history of brightest cluster galaxies is an
important topic in galaxy formation. Utilizing the Planck Sunyaev-Zel'dovich
cluster catalog, and applying the Ansatz that the most massive halos at one
redshift remain among the most massive ones at a slightly later cosmic epoch,
we have constructed cluster samples at redshift z~0.4 and z~0.2 that can be
statistically regarded as progenitor-descendant pairs. This allows us to study
the stellar mass assembly history of BCGs in these massive clusters at late
times, finding the degree of growth between the two epochs is likely at only
few percent level, which is far lower compared to the prediction from a
state-of-the-art semi-analytic galaxy formation model.
