Degree-scale anomalies in the CMB: localizing the first peak dip to a small patch of the north ecliptic sky

TL;DR

This paper investigates localized anomalies in the CMB power spectrum, specifically a persistent suppression of the first Doppler peak near the north ecliptic pole across multiple WMAP data releases, challenging standard cosmological models.

Contribution

It identifies a consistent, localized suppression of the first CMB peak in the north ecliptic sky across different WMAP datasets, suggesting a potential new anomaly.

Findings

Suppression of the first Doppler peak near the north ecliptic pole

Persistence of the anomaly across multiple WMAP data releases

Implications for cosmological parameter estimation

Abstract

Noticeable deviations from the prediction of the fiducial LCDM cosmology are found in the angular power spectrum of the CMB. Besides large-angle anomalies, the WMAP 1st year data revealed a dip in the power spectrum at l \sim 200, which seemed to disappear in the 3rd year and subsequent angular power spectra. Using the WMAP 1st, 3rd, and 5th year data as well as the 5 year coadded data, we study the intensity and spatial distribution of this feature in order to unveil its origin and its implications for the cosmological parameters. We show that in all WMAP data releases there is a substantial suppression of the first Doppler peak in a region near the north ecliptic pole.