Local Voids as the Origin of Large-Angle Cosmic Microwave Background Anomalies: The Effect of a Cosmological Constant
Local Voids as the Origin of Large-Angle Cosmic Microwave Background Anomalies: The Effect of a Cosmological Constant
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DOI：
10.1086/517603
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发表时间：
2006-12
期刊：
影响因子：
--
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
在具有宇宙学常数的平坦Friedmann-Robertson-步行者宇宙中，研究了由均匀的局部尘埃填充空洞引起的宇宙微波背景辐射的大角尺度温度各向异性.与Einstein-de Sitter背景下的等效尘埃填充空洞模型相比，由于二阶效应增强了线性积分的Sachs-Wolfe（ISW）效应，补偿后的渐近膨胀局域空洞的各向异性可以更大.然而，对于膨胀足够快于壁的渐近速度的局部空隙，二阶效应可以抑制由于线性ISW效应引起的波动。一对半径为（2-3）× 102 h-1 Mpc、物质密度差为δm-0.3的准线性补偿渐近局域空洞可以作为冷点观测到，其温度各向异性为ΔT/T ~ O（10-5），这可能有助于解释观测到的大角度CMB异常。我们预测，相关的各向异性在当地的哈勃常数的方向上的空隙可能是几个百分点大。
We explore the large angular scale temperature anisotropies in the cosmic microwave background (CMB) due to homogeneous local dust-filled voids in a flat Friedmann-Robertson-Walker universe with a cosmological constant. In comparison with the equivalent dust-filled void model in the Einstein-de Sitter background, we find that the anisotropy for compensated asymptotically expanding local voids can be larger, because second-order effects enhance the linear integrated Sachs-Wolfe (ISW) effect. However, for local voids that expand sufficiently faster than the asymptotic velocity of the wall, the second-order effect can suppress the fluctuation due to the linear ISW effect. A pair of quasi-linear compensated asymptotic local voids with radius (2-3) × 102 h-1 Mpc and a matter density contrast δm ~ -0.3 can be observed as cold spots with a temperature anisotropy ΔT/T ~ O(10-5) that might help explain the observed large-angle CMB anomalies. We predict that the associated anisotropy in the local Hubble constant in the direction of the voids could be as large as a few percent.