Weak Lensing of the CMB: Power Spectrum Covariance
Weak Lensing of the CMB: Power Spectrum Covariance
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CMB 的弱透镜效应：功率谱协方差
DOI：
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发表时间：
2001
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通讯作者：
A. Cooray
中科院分区：
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作者：
A. Cooray
讨论了弱引力透镜角偏差对宇宙微波背景辐射各向异性功率谱协方差的非高斯贡献，以及这些偏差与大尺度结构产生的次级温度涨落源（如积分Sachs-Wolfe效应和Sunyave-Zel'dovich效应）的相关性。这种额外的贡献的协方差分箱角功率谱，超出了众所周知的宇宙方差和任何相关的仪器噪声，结果从一个三谱，或四点相关函数，在温度各向异性数据。在多极空间中有相当宽的仓，从透镜效应到仓功率谱方差的非高斯贡献对于几千个多极来说是微不足道的，并且不太可能影响具有声学峰值和阻尼尾部的宇宙学参数估计。然而，在解释对应于几弧分及更小的角尺度的几千个多极子的分箱CMB功率谱测量值时，应考虑对协方差的非高斯贡献。
We discuss the non-Gaussian contribution to the power spectrum covariance of cosmic microwave background (CMB) anisotropies resulting through weak gravitational lensing angular deflections and the correlation of deflections with secondary sources of temperature fluctuations generated by the large scale structure, such as the integrated Sachs-Wolfe effect and the Sunyave-Zel’dovich effect. This additional contribution to the covariance of binned angular power spectrum, beyond the well known cosmic variance and any associated instrumental noise, results from a trispectrum, or a four point correlation function, in temperature anisotropy data. With substantially wide bins in multipole space, the resulting non-Gaussian contribution from lensing to the binned power spectrum variance is insignificant out to multipoles of a few thousand and is not likely to affect the cosmological parameter estimation with acoustic peaks and the damping tail. The non-Gaussian contribution to covariance, however, should be considered when interpreting binned CMB power spectrum measurements at multipoles of a few thousand corresponding to angular scales of few arcminutes and less.