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arXiv 0712.1291astro-phgr-qc
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Lambda主导的扁平宇宙中CMB温度各向异性的二阶引力效应

Second Order Gravitational Effects on CMB Temperature Anisotropy in Lambda dominated flat universes

Kenji Tomita, Kaiki Taro Inoue

摘要:

研究了具有物质和宇宙学常数$Λ$的平坦宇宙中局域不均匀性对宇宙微波背景辐射的二阶引力效应。我们发现,广义相对论修正的牛顿近似是可以忽略不计的,在第二阶的非均匀区域的大小是足够小的视界尺度。对于球对称的礼帽型准线性扰动,对应于线性积分的Sachs-Wolfe(ISW)效应的一阶温度波动被补偿的空洞(块)的二阶温度波动增强(抑制)。作为局域不均匀性红移的函数,对于一定的同动尺寸和密度衬度,由引力势演化引起的二阶温度涨落在物质- $Λ$相等历元之前有一个峰值.红移z~1处局域准线性不均匀性的二阶引力效应可能对宇宙微波背景产生重要影响。

英文摘要:

We study second order gravitational effects of local inhomogeneities on the cosmic microwave background radiation in flat universes with matter and a cosmological constant $Λ$. We find that the general relativistic correction to the Newtonian approximation is negligible at second order provided that the size of the inhomogeneous region is sufficiently smaller than the horizon scale. For a spherically symmetric top-hat type quasi-linear perturbation, the first order temperature fluctuation corresponding to the linear integrated Sachs-Wolfe (ISW) effect is enhanced(suppressed) by the second order one for a compensated void(lump). As a function of redshift of the local inhomogeneity, the second order temperature fluctuations due to evolution of the gravitational potential have a peak before the matter-$Λ$ equality epoch for a fixed comoving size and a density contrast. The second order gravitational effects from local quasi-linear inhomogeneities at a redshift z~1 may significantly affect the cosmic microwave background.

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