Environmental dependence of different colors in the CMASS sample of the
  SDSS DR9
  In this study, I investigate the environmental dependence of galaxy colors in
the CMASS sample of the Sloan Digital Sky Survey Data Release 9 (SDSS DR9). To
decrease the radial selection effect, I divide the CMASS sample into subsamples
with a redshift binning size of 0.01 and analyze the environmental dependence
of the u-r, u-g, g-r, r-i and i-z colors for these subsamples in each redshift
bin. Statistical analysis shows that all the five colors weakly correlate with
the local environment, which may mean that the environmental processes
responsible for a galaxy's properties proceed slowly over cosmic time.
