Breaking of self-averaging properties and selection effects in the
  Luminous Red Galaxies sample
  We study the statistical properties of the Luminous Red Galaxies sample from
the Sloan Digital Sky Survey. In particular we test, by determining the
probability density function (PDF) of galaxy (conditional) counts in spheres,
whether statistical properties are self-averaging within the sample. We find
that there are systematic differences in the shape of the PDF and in the
location of its peak, signaling that there are major systematic effects in the
data which make the estimation of volume average quantities unreliable within
this sample. We discuss that these systematic effects are related to the
fluctuating behavior of the redshift counts which can be originated by
intrinsic fluctuations in the galaxy density field or by observational
selection effects. The latter possibility implies that more than 20 % of the
galaxies have not been observed and that such a selection should not be a
smooth function of redshift.
