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arXiv 1701.08552astro-ph.CO
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CMB温度大尺度峰的局部性质

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

A. Marcos-Caballero, E. Martínez-González, P. Vielva

摘要:

在目前的工作中,我们研究的最大结构的CMB温度测量普朗克在天空中,其中,特别是位于南银河半球的最突出的峰值。除了这些大尺度特征外,分析中还包括著名的冷点异常。所有这些峰值都将对某些CMB大尺度异常做出重要贡献,如宇称和半球不对称性,偶极调制,四极和八极之间的对齐,或者在冷点的情况下,场的非高斯性。峰的分析是通过使用它们的多极配置文件,其特征在于在方位角的离散傅立叶变换的峰值的局部形状。为了量化峰的局部各向异性,多极分布的相位的分布进行了研究,通过使用瑞利随机游走方法。最后,为了考虑到银河掩模的影响,对峰周围的二维场进行了直接分析。分析的结果得出结论,一旦中心处的峰值幅度及其一阶和二阶导数被调节,场的其余部分与标准模型兼容。特别是,它被观察到的冷点异常所造成的曲率在中心的大值。

英文摘要:

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.

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