Probing of the Interactions Between the Hot Plasmas and Galaxies in
  Clusters from z=0.1 to 0.9
  Based on optical and X-ray data for a sample of 34 relaxed rich clusters of
galaxies with redshifts of 0.1-0.9, we studied relative spatial distributions
of the two major baryon contents, the cluster galaxies and the hot plasmas.
Using multi-band photometric data taken with the UH88 telescope, we determined
the integrated (two dimensional) radial light profiles of member galaxies in
each cluster using two independent approaches, i.e., the background subtraction
and the color-magnitude filtering. The ICM mass profile of each cluster in our
sample, also integrated in two dimensions, was derived from a
spatially-resolved spectral analysis using XMM-Newton and Chandra data. Then,
the radially-integrated light profile of each cluster was divided by its ICM
mass profile, to obtain a profile of "galaxy light vs. ICM mass ratio". The
ratio profiles over the central 0.65 R500 regions were found to steepen from
the higher- to lower- redshift subsamples, meaning that the galaxies become
more concentrated in the ICM sphere towards lower redshifts. The evolution is
also seen in galaxy number vs. ICM mass ratio profiles. A range of systematic
uncertainties in the galaxy light measurements, as well as many
radius-/redshift- dependent biases to the galaxy vs. ICM profiles have been
assessed, but none of them is significant against the observed evolution.
Besides, the galaxy light vs. total mass ratio profiles also exhibit gradual
concentration towards lower redshift. We interpret in the context that the
galaxies, the ICM, and the dark matter components followed a similar spatial
distribution in the early phase (z>0.5), while the galaxies have fallen towards
the center relative to the others at a later phase.
