Measurable Relationship Between Bright Galaxies and Their Faint
  Companions in WHL J085910.0+294957, a Galaxy Cluster at z = 0.30: Vestiges of
  Infallen Groups?
  The properties of satellite galaxies are closely related to their host
galaxies in galaxy groups. In cluster environments, on the other hand, the
interaction between close neighbors is known to be limited. Our goal is to
examine the relationships between host and satellite galaxies in the harsh
environment of a galaxy cluster. To achieve this goal, we study a galaxy
cluster WHL J085910.0+294957 at z = 0.30 using deep images obtained with CQUEAN
CCD camera mounted on the 2.1-m Otto Struve telescope. After member selection
based on the scaling relations of photometric and structural parameters, we
investigate the relationship between bright (M_i < -18) galaxies and their
faint (-18 < M_i < -15) companions. The weighted mean color of faint companion
galaxies shows no significant dependence (< 1 sigma to Bootstrap uncertainties)
on cluster-centric distance and local luminosity density as well as the
luminosity and concentration of an adjacent bright galaxy. However, the
weighted mean color shows marginal dependence (~ 2.2 sigma) on the color of an
adjacent bright galaxy, when the sample is limited to bright galaxies with at
least 2 faint companions. By using a permutation test, we confirm that the
correlation in color between bright galaxies and their faint companions in this
cluster is statistically significant with a confidence level of 98.7%. The
statistical significance increases if we additionally remove non-members using
the SDSS photometric redshift information (~ 2.6 sigma and 99.3%). Our results
suggest three possible scenarios: (1) vestiges of infallen groups, (2) dwarf
capturing, and (3) tidal tearing of bright galaxies.
