Footprints of statistical anisotropies
Footprints of statistical anisotropies
复制标题
统计各向异性的足迹
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
C. Armendariz
中科院分区：
文献类型：
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作者：
C. Armendariz
我们提出并发展了一种形式主义来描述和约束统计上各向异性的原始扰动。从球谐函数中的原始功率谱的分解开始，我们发现在 CMB 天空中观测到的温度波动如何与该谐波展开中的系数直接相关。尽管角功率谱不区分统计各向同性和各向异性扰动，但可以定义作为统计各向异性直接测量的类似二次估计量。作为形式主义的简单说明，我们使用全天 CMB 地图来测试原始扰动中是否存在首选方向。我们没有找到支持原始光谱中偶极子分量存在的重要证据。
We propose and develop a formalism to describe and constrain statistically anisotropic primordial perturbations. Starting from a decomposition of the primordial power spectrum in spherical harmonics, we find how the temperature fluctuations observed in the CMB sky are directly related to the coefficients in this harmonic expansion. Although the angular power spectrum does not discriminate between statistically isotropic and anisotropic perturbations, it is possible to define analogous quadratic estimators that are direct measures of statistical anisotropy. As a simple illustration of our formalism we test for the existence of a preferred direction in the primordial perturbations using full-sky CMB maps. We do not find significant evidence supporting the existence of a dipole component in the primordial spectrum.