The SAMI Galaxy Survey: mass as the driver of the kinematic morphology -
  density relation in clusters
  We examine the kinematic morphology of early-type galaxies (ETGs) in eight
galaxy clusters in the Sydney-AAO Multi-object Integral field spectrograph
(SAMI) Galaxy Survey. The clusters cover a mass range of
14.2<log(M_200/M_odot)<15.2 and we measure spatially-resolved stellar
kinematics for 315 member galaxies with stellar masses
10.0<log(M_*/M_odot)<11.7 within 1R_200 of the cluster centers. We calculate
the spin parameter, lambda_R and use that to classify the kinematic morphology
of the galaxies as fast or slow rotators. The total fraction of slow rotators
in the early-type galaxy population, F_SR=0.14+/-0.02 and does not depend on
host cluster mass. Across the eight clusters, the fraction of slow rotators
increases with increasing local overdensity. We also find that the slow-rotator
fraction increases at small clustercentric radii (R_cl<0.3R_200), and note that
there is also an increase in slow-rotator fraction at R_cl~0.6R_200. The slow
rotators at these larger radii reside in cluster substructure. We find the
strongest increase in slow-rotator fraction occurs with increasing stellar
mass. After accounting for the strong correlation with stellar mass, we find no
significant relationship between spin parameter and local overdensity in the
cluster environment. We conclude that the primary driver for the kinematic
morphology--density relationship in galaxy clusters is the changing
distribution of galaxy stellar mass with local environment. The presence of
slow rotators in substructure suggests that the cluster kinematic
morphology--density relationship is a result of mass segregation of
slow-rotating galaxies forming in groups that later merge with clusters and
sink to the cluster center via dynamical friction.
