CMB Maximum Temperature Asymmetry Axis: Alignment with Other Cosmic Asymmetries

TL;DR

This study identifies a residual temperature asymmetry axis in WMAP CMB data and finds it aligns unusually closely with other cosmic asymmetries, suggesting a possible common physical origin.

Contribution

The paper introduces a new pixel-based estimator for the CMB temperature asymmetry axis and demonstrates its alignment with other cosmic asymmetries, highlighting potential new physics.

Findings

The asymmetry axes are abnormally close to each other.

The probability of the observed alignment occurring by chance is very low (0.1%-1%).

The results support the Extended Topological Quintessence model.

Abstract

We use a global pixel based estimator to identify the axis of the residual Maximum Temperature Asymmetry (MTA) (after the dipole subtraction) of the WMAP 7 year Internal Linear Combination (ILC) CMB temperature sky map. The estimator is based on considering the temperature differences between opposite pixels in the sky at various angular resolutions (4 degrees-15 degrees and selecting the axis that maximizes this difference. We consider three large scale Healpix resolutions (N_{side}=16 (3.7 degrees), N_{side}=8 (7.3 degrees) and N_{side}=4 (14.7 degrees)). We compare the direction and magnitude of this asymmetry with three other cosmic asymmetry axes (\alpha dipole, Dark Energy Dipole and Dark Flow) and find that the four asymmetry axes are abnormally close to each other. We compare the observed MTA axis with the corresponding MTA axes of 10^4 Gaussian isotropic simulated ILC maps (based on LCDM). The fraction of simulated ILC maps that reproduces the observed magnitude of the MTA asymmetry and alignment with the observed \alpha dipole is in the range of 0.1%-0.5%$ (depending on the resolution chosen for the CMB map). The corresponding magnitude+alignment probabilities with the other two asymmetry axes (Dark Energy Dipole and Dark Flow) are at the level of about 1%. We propose Extended Topological Quintessence as a physical model qualitatively consistent with this coincidence of directions.