1209.1174 (Wen Zhao)

Local properties of WMAP Cold Spot    [PDF]

Wen Zhao

We investigate the local properties of WMAP Cold Spot (CS) localized at ($l=209^{\circ}, b=-57^{\circ}$) in Galactic Coordinate by defining the local statistics: mean temperature, variance, skewness and kurtosis. Comparing with the Gaussian random simulations, as well as the other spots in WMAP data, we find that the local mean temperatures around CS are quite lower in the scale of $R\lesssim5^{\circ}$ as expected. In particular, we also find that 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 prefer a large-scale non-Gaussian structure to a combination of some small structures. The non-Gaussianity of CS is totally encoded in the WMAP low multipoles at $l\le 40$. We also find that the cosmic texture can excellently explain all the excesses in these statistics. So the local analysis of the WMAP CS supports the cosmic texture explanation.

View original: http://arxiv.org/abs/1209.1174