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arXiv 0812.1406astro-ph
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发光红星系的三维亏格拓扑

3D Genus Topology of Luminous Red Galaxies

J. Richard Gott, Yun-Young Choi, Changbom Park, Juhan Kim

摘要:

我们使用斯隆数字巡天中的发光红星系(LRGs)测量了大尺度结构的3D亏格拓扑,发现它与最简单的暴胀场景所期望的高斯随机相位初始条件一致。这是有史以来最大规模的3D拓扑研究。拓扑结构类似海绵。我们在两个体积有限的样本中测量拓扑:一个密集的浅样本,平滑长度为21 h ^{-1}Mpc,一个稀疏的深样本,平滑长度为34 h ^{-1}Mpc。亏格曲线的振幅以4%的不确定度测量。非线性偏置和引力效应引起的亏格曲线的小变形,通过N体模拟利用暗晕探测技术定位LRG得到了很好的解释(精度约为1-σ)。这表明LRG的形成是一个干净的问题,可以很好地建模,没有任何自由拟合参数。这预示着在未来的深红移巡天中,利用长周期射电群测量重子振荡尺度等特征尺度是一个好兆头。

英文摘要:

We measure the 3D genus topology of large scale structure using Luminous Red Galaxies (LRGs) in the Sloan Digital Sky Survey and find it consistent with the Gaussian random phase initial conditions expected from the simplest scenarios of inflation. This studies 3D topology on the largest scales ever obtained. The topology is sponge-like. We measure topology in two volume-limited samples: a dense shallow sample studied with smoothing length of 21h^{-1}Mpc, and a sparse deep sample studied with a smoothing length of 34h^{-1}Mpc. The amplitude of the genus curve is measured with 4% uncertainty. Small distortions in the genus curve expected from non-linear biasing and gravitational effects are well explained (to about 1-σaccuracy) by N-body simulations using a subhalo-finding technique to locate LRGs. This suggests the formation of LRGs is a clean problem that can be modeled well without any free fitting parameters. This bodes well for using LRGs to measure the characteristic scales such as the baryon oscillation scale in future deep redshift surveys.

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