Local Voids as the Origin of Large-Angle Cosmic Microwave Background Anomalies. I.
Local Voids as the Origin of Large-Angle Cosmic Microwave Background Anomalies. I.
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DOI：
10.1086/505636
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
K. T. Inoue;J. Silk
中科院分区：
文献类型：
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作者：
K. T. Inoue;J. Silk
我们探讨了宇宙微波背景辐射中由于红移z = 1的均匀局域空洞膨胀而产生的大角尺度温度各向异性。一个半径约为3 × 102 h-1 Mpc、密度差δ约为-0.3的补偿球对称均匀尘埃填充空洞可以被观测到为一个温度各向异性为ΔT/T ~ -1 × 10-5的冷点，周围环绕着一个稍热的环。我们发现，一对这些圆形的冷点分开约50°可以解释的八极的平面性和四极和八极之间的宇宙微波背景（CMB）各向异性的对齐。银河系南半球的冷点在~3 σ水平上是异常的，可以用z ~ 1处的大空洞来解释。在大角度CMB功率中观察到的南北不对称性可以归因于这些局部空隙在两个半球之间的不对称分布。低四极子的统计意义进一步降低在这种解释的大角度尺度CMB异常。
We explore the large angular scale temperature anisotropies in the cosmic microwave background due to expanding homogeneous local voids at redshift z ≲ 1. A compensated spherically symmetric homogeneous dust-filled void with radius ~3 × 102 h-1 Mpc and density contrast δ ~ -0.3 can be observed as a cold spot with a temperature anisotropy ΔT/T ~ -1 × 10-5 surrounded by a slightly hotter ring. We find that a pair of these circular cold spots separated by ~50° can account both for the planarity of the octopole and for the alignment between the quadrupole and the octopole in the cosmic microwave background (CMB) anisotropy. The cold spot in the Galactic southern hemisphere, which is anomalous at the ~3 σ level, can be explained by such a large void at z ~ 1. The observed north-south asymmetry in the large-angle CMB power can be attributed to the asymmetric distribution of these local voids between the two hemispheres. The statistical significance of the low quadrupole is further reduced in this interpretation of the large angular scale CMB anomalies.