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arXiv 1105.5249astro-ph.CO
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Rees-Sciama效应及前景结构对星系红移的影响

Rees--Sciama Effect and Impact of Foreground Structures on Galaxy Redshifts

Hu Zhan

备注：
8 pages, 4 figures, ApJ accepted
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摘要：

我们估计的Rees-Sciama（RS）的超级结构上的宇宙微波背景（CMB）的温度波动的影响，并确定一个相关的影响星系红移。通过数值求解测地线方程，我们发现超团簇和超空都能使CMB中心区域的温度降低几个微开尔文，而周围区域的温度由于RS效应而略有升高。RS效应的两个组成部分，红移和引力时间延迟，在很大程度上相互抵消，对同时从扭曲的最后一个散射表面开始的CMB光子产生等效但小得多的影响。对于星系，时间延迟效应与红移效应是可以分离的，并且由超级结构引起的红移的微小变化可以在大尺度均方根体速度的百分比水平上，这可能只能通过统计检测到。在更小的尺度上，强透镜源的两个图像之间的微小红移差异通常应该存在，这与源红移处的哈勃膨胀率有关。然而，正如Loeb（1998）所指出的，观测问题和结构的自行将使这样的测量成为不可能。

英文摘要：

We estimate the Rees--Sciama (RS) effect of super structures on the cosmic microwave background (CMB) temperature fluctuations and identify a related effect on galaxy redshifts. By numerically solving the geodesic equation, we find that both superclusters and supervoids can decrease the temperature of the CMB by several micro Kelvin in the central region and increase the temperature slightly in the surrounding area due to the RS effect. The two components of the RS effect, redshift and gravitational time delay, largely cancel each other, leaving an equivalent but much smaller effect on the CMB photons that started out at the same time from the distorted last scattering surface. For galaxies, the time delay effect is separable from the redshift effect, and the slight change to the redshift induced by super structures can be at the percent level of large-scale rms bulk velocities, which might only be detected statistically. On much smaller scales, a tiny redshift difference between two images of a strongly lensed source should exist in general, which is related to the Hubble expansion rate at the source redshift. However, as Loeb (1998) pointed out, observational issues and the proper motion of the structure would make such a measurement impossible.

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