Are There Echoes From The Pre-Big Bang Universe? A Search for Low Variance Circles in the CMB Sky

TL;DR

This study reevaluates claims of low variance circles in the CMB sky, finding they are consistent with Gaussian fluctuations predicted by inflationary cosmology, rather than evidence of pre-Big Bang phenomena.

Contribution

It critically assesses previous claims of low variance circles in the CMB, demonstrating they are statistically consistent with standard inflationary models.

Findings

Circles are not statistically significant anomalies.

All three groups of circles are consistent with Gaussian CMB fluctuations.

No evidence supporting pre-Big Bang echoes was found.

Abstract

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.