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arXiv 0809.3734astro-ph
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星系团大尺度奇异速度的测量:结果和宇宙学意义

A measurement of large-scale peculiar velocities of clusters of galaxies: results and cosmological implications

A. Kashlinsky, F. Atrio-Barandela, D. Kocevski, H. Ebeling

摘要:

星系团的特殊速度可以通过研究星系团内部炽热的X射线发射气体对微波光子的散射所产生的宇宙微波背景(CMB)的涨落来测量。虽然对于单个簇,这样的测量导致大的误差,但是簇的大的统计样本允许研究由样本的整体整体流量主导的累积量,其中统计误差向下积分。我们目前的结果,从这样的测量使用最大的全天X射线星团目录相结合的日期和3年的WMAP CMB数据。我们发现了一个强大的和连贯的整体流的尺度至少超过300 h^{-1} Mpc,我们的目录的限制。这种流动很难在和谐LCDM模型的框架内用引力演化来解释,并且可能表明遥远的前暴胀不均匀性在整个当前视界上施加的倾斜。

英文摘要:

Peculiar velocities of clusters of galaxies can be measured by studying the fluctuations in the cosmic microwave background (CMB) generated by the scattering of the microwave photons by the hot X-ray emitting gas inside clusters. While for individual clusters such measurements result in large errors, a large statistical sample of clusters allows one to study cumulative quantities dominated by the overall bulk flow of the sample with the statistical errors integrating down. We present results from such a measurement using the largest all-sky X-ray cluster catalog combined to date and the 3-year WMAP CMB data. We find a strong and coherent bulk flow on scales out to at least > 300 h^{-1} Mpc, the limit of our catalog. This flow is difficult to explain by gravitational evolution within the framework of the concordance LCDM model and may be indicative of the tilt exerted across the entire current horizon by far-away pre-inflationary inhomogeneities.

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