Local properties of WMAP Cold Spot

TL;DR

This paper analyzes the WMAP Cold Spot's local properties, revealing significant non-Gaussianity at large scales and suggesting cosmic texture as a plausible explanation for its anomalies.

Contribution

It introduces a detailed local statistical analysis of the Cold Spot and demonstrates that cosmic texture can account for its observed anomalies.

Findings

WMAP Cold Spot deviates from Gaussianity at ~99% significance

Local variance and skewness are larger around the Cold Spot at scales >5°

Cosmic texture explains all observed anomalies in the statistics

Abstract

We investigate the local properties of WMAP Cold Spot (CS) by defining the local statistics: mean temperature, variance, skewness and kurtosis. We find that, compared with the \emph{coldest spots} in random Gaussian simulations, WMAP CS deviates from Gaussianity at $\sim 99%$ significant level. In the meanwhile, when compared with the spots at the same position in the simulated maps, the values of local variance and skewness around CS are all systematically larger in the scale of $R>5^{\circ}$, which implies that WMAP CS is a large-scale non-Gaussian structure, rather than a combination of some small structures. This is consistent with the finding that the non-Gaussianity of CS is totally encoded in the WMAP low multipoles. Furthermore, we find that the cosmic texture can excellently explain all the anomalies in these statistics.