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arXiv 1408.4648astro-ph.CO
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红移-空间星系两点关联函数与重子声学振荡

The redshift-space galaxy two-point correlation function and baryon acoustic oscillations

Donghui Jeong, Liang Dai, Marc Kamionkowski, Alexander S. Szalay

摘要:

未来的星系巡天将测量具有重要意义的重子声学振荡(BAO),全面了解BAO在红移空间中的各向异性对于探索BAO中的宇宙学信息具有重要意义。在这里,我们描述的各向异性,出现在红移空间的星系两点关联函数(2 PCF)和阐明的起源的功能,出现在依赖的BAO的星系对的方向和视线之间的角度。我们这样做的配置空间2 PCF使用流模型的推导。我们发现,与通常的看法相反,在红移空间2 PCF的BAO峰的位置是各向异性的,即使在线性理论。BAO的各向异性强烈依赖于提取峰值的方法,显示最大3%的角度变化。我们还发现,提取的BAO峰的$r^2ξ(r,μ)$显着降低的各向异性子百分之一级的角度变化。当减去由于2 PCF的宽带行为引起的倾斜时,由于朝向BAO凸起的局部下落速度,BAO凸起沿着视线增强。精确测量红移空间2 PCF的角度依赖性将允许对BAO之外的暗能量进行新的几何测试。

英文摘要:

Future galaxy surveys will measure baryon acoustic oscillations (BAOs) with high significance, and a complete understanding of the anisotropies of BAOs in redshift space will be important to exploit the cosmological information in BAOs. Here we describe the anisotropies that arise in the redshift-space galaxy two-point correlation function (2PCF) and elucidate the origin of features that arise in the dependence of the BAOs on the angle between the orientation of the galaxy pair and the line of sight. We do so with a derivation of the configuration-space 2PCF using streaming model. We find that, contrary to common belief, the locations of BAO peaks in the redshift-space 2PCF are anisotropic even in the linear theory. Anisotropies in BAO depend strongly on the method of extracting the peak, showing maximum 3 % angular variation. We also find that extracting the BAO peak of $r^2ξ(r,μ)$ significantly reduces the anisotropy to sub-percent level angular variation. When subtracting the tilt due to the broadband behavior of the 2PCF, the BAO bump is enhanced along the line of sight because of local infall velocities toward the BAO bump. Precise measurement of the angular dependence of the redshift-space 2PCF will allow new geometrical tests of dark energy beyond the BAO.

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