Title: The weird side of the CMB: Cold Spot

Speaker: Wen Zhao (USTC)  

Time & Place: Thursday, 3:00pm, December 11th, Lecture Hall, 3rd floor  

Abstract: Both WMAP and Planck data show a number of large-scale anomalies in the CMB temperature anisotropies, which may indicate some unsolved contamination, systematic, or new physics in the early Universe. In this talk, I will focus on the well-known CMB "Cold Spot" found by WMAP, and confirmed by Planck. By defining the local statistics: Mean Temperature, Variance, Skewness, Kurtosis, and the Minkowski Functionals, we study the local properties of the CMB "Cold Spot", and find it deviates from the Gaussianity at ~ 99 percent significant level. We also find that this Cold Spot is a large-scale non-Gaussian structure, rather than a combination of some small structures, and the non-Gaussianity is totally encoded in the CMB low multipoles. Furthermore, we find that the cosmic texture can excellently explain all the anomalies of these statistics.

Biog: TBC