  Mass segregation, a tendency of more massive galaxies being distributed
closer to the cluster center, is naturally expected from dynamical friction,
but its presence is still controversial. Using deep optical observations of 14
Abell clusters (KYDISC) and a set of hydrodynamic simulations (YZiCS), we find
in some cases a hint of mass segregation inside the virial radius. Segregation
is visible more clearly when the massive galaxy fraction is used instead of
mean stellar mass. The trend is more significant in the simulations than in the
observations. To find out the mechanisms working on mass segregation, we look
into the evolution of individual clusters simulated. We find that the degree of
mass segregation is different for different clusters: the trend is visible only
for low-mass clusters. We compare the masses of galaxies and their dark haloes
at the time of infall and at the present epoch to quantify the amount of tidal
stripping. We then conclude that satellites that get accreted at earlier epochs
or galaxies in more massive clusters go through more tidal stripping. These
effects in combination result in a correlation between the host halo mass and
the degree of stellar mass segregation.
