Multiwavelength investigations of co-evolution of bright custer galaxies
  We report a systematic multi-wavelength investigation of environments of the
brightest cluster galaxies (BCGs), using the X-ray data from the Chandra
archive, and optical images taken with 34'x 27' field-of-view Subaru
Suprime-Cam. Our goal is to help understand the relationship between the BCGs
and their host clusters, and between the BCGs and other galaxies, to eventually
address a question of the formation and co-evolution of BCGs and the clusters.
  Our results include: 1) Morphological variety of BCGs, or the second or the
third brightest galaxy (BCG2, BCG3), is comparable to that of other bright red
sequence galaxies, suggesting that we have a continuous variation of morphology
between BCGs, BCG2, and BCG3, rather than a sharp separation between the BCG
and the rest of the bright galaxies. 2) The offset of the BCG position relative
to the cluster centre is correlated to the degree of concentration of cluster
X-ray morphology (Spearman rho = -0.79), consistent with an interpretation that
BCGs tend to be off-centered inside dynamically unsettled clusters. 3)
Morphologically disturbed clusters tend to harbour the brighter BCGs, implying
that the "early collapse" may not be the only major mechanism to control the
BCG formation and evolution.
