Bianchi VII_h models and the cold spot texture

TL;DR

This paper reevaluates Bianchi VII_h cosmological models in light of the possibility that the CMB cold spot is due to a cosmic texture, finding that the models are now less supported by the data.

Contribution

The study revisits previous Bianchi VII_h analyses considering the cold spot as a cosmic texture, showing the models are less favored after data correction.

Findings

Both models are now unconstrained by the data.

Bayesian evidence for both models is significantly reduced.

The cold spot likely influences previous Bianchi VII_h detections.

Abstract

We have returned to our previous Bianchi VII_h analysis in light of the Cruz et al. 2007 suggestion that the cold spot observed near the southern Galactic pole may be a remnant temperature perturbation of a cosmic texture. In Bridges et al. 2006b we found two favoured left handed Bianchi VII_h templates with restricted prior probabilities so that the template was centred close to the cold spot. Using WMAP data `corrected' for the texture fit we have now reexamined both models to assess any changes to these conclusions. We find that both models are left almost entirely unconstrained by the data and consequently exhibit significantly reduced Bayesian evidences. Both models are now disfavoured by the data. This result reinforces our previous suggestion that the cold spot was likely to be driving any Bianchi VII_h detection.