The Angular bispectrum of the cosmic microwave background
The Angular bispectrum of the cosmic microwave background
复制标题
宇宙微波背景的角双谱
DOI：
10.1086/187367
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Xiaochun Luo
中科院分区：
文献类型：
--
作者：
Xiaochun Luo
COBE为我们提供了CBR各向异性的全天图。然而，即使在四年COBE数据可用时噪声水平可以忽略不计，宇宙方差也会阻止我们获得有关原始波动高斯性质的信息。这个重要的问题是解决在这里通过研究宇宙微波背景各向异性的角双谱。给出了角双谱的一般形式，并计算了高斯涨落角双谱的宇宙方差。使用角双谱的优点是可以选择使用多极矩，使宇宙方差项最小化。与宇宙方差相比，大多数物理激励的非高斯模型中的非高斯信号都很小。除非振幅很大，非高斯信号仅在那些角双谱平坦或随多极矩增加而增加的模型中的COBE数据中可检测到。
COBE has provided us with a whole-sky map of the CBR anisotropies. However, even if the noise level is negligible when the four year COBE data are available, the cosmic variance will prevent us from obtaining information about the Gaussian nature of the primordial fluctuations. This important issue is addressed here by studying the angular bispectrum of the cosmic microwave background anisotropies. A general form of the angular bispectrum is given and the cosmic variance of the angular bispectrum for Gaussian fluctuations is calculated. The advantage of using the angular bispectrum is that one can choose to use the multipole moments which minimize the cosmic variance term. The non-Gaussian signals in most physically motivated non-Gaussian models are small compared with cosmic variance. Unless the amplitudes are large, the non-Gaussian signals are only detectable in the COBE data in those models where the angular bispectrum is flat or increases with increasing multipole moment.