Small-Scale Conformity of the Virgo Cluster Galaxies
  We investigate the small-scale conformity in color between bright galaxies
and their faint companions in the Virgo cluster. Cluster member galaxies are
spectroscopically determined using the Extended Virgo Cluster Catalog (EVCC)
and the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). We find that the
luminosity-weighted mean color of faint galaxies depends on the color of
adjacent bright galaxy as well as on the cluster-scale environment
(gravitational potential index). From this result for the entire area of the
Virgo cluster, it is not distinguishable whether the small-scale conformity is
genuine or is artificially produced due to cluster-scale variation of galaxy
color. To disentangle this degeneracy, we divide the Virgo cluster area into
three sub-areas so that the cluster-scale environmental dependence is
minimized: A1 (central), A2 (intermediate) and A3 (outermost). We find
conformity in color between bright galaxies and their faint companions
(color-color slope significance S ~ 2.73 sigma and correlation coefficient cc ~
0.50) in A2, where the cluster-scale environmental dependence is almost
negligible. On the other hand, the conformity is not significant or very
marginal (S ~ 1.75 sigma and cc ~ 0.27) in A1. The conformity is not
significant either in A3 (S ~ 1.59 sigma and cc ~ 0.44), but the sample size is
too small in this area. These results are consistent with a scenario in which
the small-scale conformity in a cluster is a vestige of infallen groups and
these groups lose conformity as they come closer to the cluster center.
