# Local properties of the large-scale peaks of the CMB temperature

## TL;DR

This study analyzes the largest CMB temperature peaks, including the Cold Spot, using multipolar profiles and phase distributions to understand their role in large-scale anomalies, finding the Cold Spot's curvature explains its anomaly.

## Contribution

The paper introduces a detailed peak analysis using multipolar profiles and phase distributions to investigate the origin of large-scale CMB anomalies, including the Cold Spot.

## Key findings

- Peak properties are consistent with the standard model after conditioning on amplitude and derivatives.
- The Cold Spot anomaly is attributed to a large curvature at its center.
- Local anisotropy measures align with Gaussian expectations once peak parameters are fixed.

## Abstract

In the present work, we study the largest structures of the CMB temperature measured by Planck in terms of the most prominent peaks on the sky, which, in particular, are located in the southern galactic hemisphere. Besides these large-scale features, the well-known Cold Spot anomaly is included in the analysis. All these peaks would contribute significantly to some of the CMB large-scale anomalies, as the parity and hemispherical asymmetries, the dipole modulation, the alignment between the quadrupole and the octopole, or in the case of the Cold Spot, to the non-Gaussianity of the field. The analysis of the peaks is performed by using their multipolar profiles, which characterize the local shape of the peaks in terms of the discrete Fourier transform of the azimuthal angle. In order to quantify the local anisotropy of the peaks, the distribution of the phases of the multipolar profiles is studied by using the Rayleigh random walk methodology. Finally, a direct analysis of the 2-dimensional field around the peaks is performed in order to take into account the effect of the galactic mask. The results of the analysis conclude that, once the peak amplitude and its first and second order derivatives at the centre are conditioned, the rest of the field is compatible with the standard model. In particular, it is observed that the Cold Spot anomaly is caused by the large value of curvature at the centre.