Hot pixel contamination in the CMB correlation function?

TL;DR

This paper investigates hot pixel contamination in WMAP CMB data, confirms its bias on large angular scales, and shows that correcting for this bias improves the fit of a cubic universe topology over the standard LCDM model.

Contribution

It identifies and corrects hot pixel bias in WMAP data, revealing a better fit of a cubic universe topology to the CMB correlation function.

Findings

Bias affects the correlation function at large angles near 180°

Corrected data favors a cubic universe topology with L≈4

Improved match to observations over standard LCDM model

Abstract

Recently, it was suggested that the map-making procedure, which is applied to the time-ordered CMB data by the WMAP team, might be flawed by hot pixels. This could lead to a bias in the pixels having an angular distance of about 141 degrees from hot pixels due to the differential measuring process of the satellite WMAP. Here, the bias is confirmed, and the temperature two-point correlation function C(theta) is reevaluated by excluding the affected pixels. It is shown that the most significant effect occurs in C(theta) at the largest angles near theta = 180 degrees. Furthermore, the corrected correlation function C(theta) is applied to the cubic topology of the Universe, and it is found that such a multi-connected universe matches the temperature correlation better than the LCDM concordance model, provided the cubic length scale is close to L=4 measured in units of the Hubble length.