Velocity segregation effects in galaxy clusters at 0.4<~z<~1.5
  Our study is meant to extend our knowledge of the galaxy color and luminosity
segregation in velocity space (VCS and VLS, resp.), to clusters at intermediate
and high redshift. Our sample is a collection of 41 clusters in the 0.4<~z<~1.5
redshift range, for a total of 4172 galaxies, 1674 member galaxies within 2R200
with photometric or spectroscopic information, as taken from the literature. We
pay attention to perform homogeneous procedures to select cluster members,
compute global cluster properties, in particular the LOS velocity dispersion
sigmaV, and separate blue from red galaxies. We find evidence of VCS in
clusters out to z~0.8 (at the 97%-99.99% c.l., depending on the test), in the
sense that the blue galaxy population has a 10-20% larger sigmaV than the red
galaxy population. Poor or no VCS is found in the High-z sample at z>=0.8. For
the first time, we detect VLS in non-local clusters and confirm that VLS only
affects the very luminous galaxies, with brighter galaxies having lower
velocities. The threshold magnitude of VLS is ~m3+0.5, where m3 is the
magnitude of the third brightest cluster galaxy, and current data suggest that
the threshold value moves to fainter magnitudes at higher redshift. We also
detect (marginal) evidence of VLS for blue galaxies. We conclude that the
segregation effects, when their study is extended to distant clusters, can be
important tracers of the galaxy evolution and cluster assembly and discuss the
poor/no evidence of VCS at high redshift.
