Missing Power vs low-l Alignments in the Cosmic Microwave Background: No Correlation in the Standard Cosmological Model

TL;DR

This study investigates the relationship between missing large-scale power and low-l multipole alignment in the CMB, concluding no significant correlation exists under the standard cosmological model.

Contribution

It provides a statistical analysis demonstrating no significant correlation between two observed CMB anomalies, clarifying their independence within the standard model.

Findings

No significant correlation between missing large-scale power and multipole alignment.

Chance of observing both anomalies simultaneously is less than 10^{-6}.

Supports the view that these anomalies are independent phenomena.

Abstract

On large angular scales (greater than about 60 degrees), the two-point angular correlation function of the temperature of the cosmic microwave background (CMB), as measured (outside of the plane of the Galaxy) by the Wilkinson Microwave Anisotropy Probe, shows significantly lower large-angle correlations than expected from the standard inflationary cosmological model. Furthermore, when derived from the full CMB sky, the two lowest cosmologically interesting multipoles, the quadrupole (l=2) and the octopole (l=3), are unexpectedly aligned with each other. Using randomly generated full-sky and cut-sky maps, we investigate whether these anomalies are correlated at a statistically significant level. We conclusively demonstrate that, assuming Gaussian random and statistically isotropic CMB anisotropies, there is no statistically significant correlation between the missing power on large angular scales in the CMB and the alignment of the l=2 and l=3 multipoles. The chance to measure the sky with both such a lack of large-angle correlation and such an alignment of the low multipoles is thus quantified to be below 10^{-6}.