Are There Echoes From The Pre-Big Bang Universe? A Search for Low
  Variance Circles in the CMB Sky
  The existence of concentric low variance circles in the CMB sky, generated by
black-hole encounters in an aeon preceding our big bang, is a prediction of the
Conformal Cyclic Cosmology. Detection of three families of such circles in WMAP
data was recently reported by Gurzadyan & Penrose (2010). We reassess the
statistical significance of those circles by comparing with Monte Carlo
simulations of the CMB sky with realistic modeling of the anisotropic noise in
WMAP data. We find that the circles are not anomalous and that all three groups
are consistent at 3sigma level with a Gaussian CMB sky as predicted by
inflationary cosmology model.
