To the center of cold spot with Planck

Abstract

The structure of the cold spot, of a non-Gaussian anomaly in the cosmic microwave background (CMB) sky detected earlier by Vielva et al. (2004, ApJ, 609, 22), is studied using the data by Planck satellite. The map obtained of the degree of stochasticity (K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a shell-type structure with a center coinciding with the minima of the temperature distribution. The shell structure is non-Gaussian at a 4σ confidence level. Such behavior of the K-map supports the void nature of the cold spot. The method applied can be used for tracing voids that have no signatures in redshift surveys. © ESO, 2014.