Anomalous parity asymmetry of the Wilkinson Microwave Anisotropy Probe power spectrum data at low multipoles

TL;DR

This paper investigates the parity asymmetry in WMAP data, finding a significant odd-parity preference at low multipoles, which may be linked to the low quadrupole power, prompting further analysis to determine its origin.

Contribution

The study identifies a statistically significant odd-parity asymmetry in WMAP power spectrum data at low multipoles, suggesting a potential cosmological or systematic origin.

Findings

Odd-parity preference at 4-in-1000 significance level.

Low quadrupole power likely related to parity asymmetry.

Further analysis needed with Planck data to determine origin.

Abstract

We have investigated non-Gaussianity of our early Universe by comparing the parity asymmetry of the WMAP power spectrum with simulations. We find that odd-parity preference of the WMAP data (2<= l <=18) is anomalous at 4-in-1000 level. We find it likely that low quadrupole power is part of this parity asymmetry rather than an isolated anomaly. Futher investigation is required to find out whether the origin of this anomaly is cosmological or systematic effect. The data from Planck surveyor, which has systematics distinct from the WMAP, will help us to resolve the origin of the anomalous odd-parity preference.