Large-Scale Anisotropic Correlation Function of SDSS Luminous Red Galaxies
Large-Scale Anisotropic Correlation Function of SDSS Luminous Red Galaxies
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DOI：
10.1086/528951
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发表时间：
2007-11
期刊：
影响因子：
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通讯作者：
T. Okumura;T. Matsubara;D. Eisenstein;I. Kayo;C. Hikage;A. Szalay;D. Schneider
中科院分区：
文献类型：
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作者：
T. Okumura;T. Matsubara;D. Eisenstein;I. Kayo;C. Hikage;A. Szalay;D. Schneider
我们研究了大尺度各向异性的两点相关函数使用46,760明亮的红色星系在红移0.16-0.47从斯隆数字巡天。为了考虑红移空间中大尺度结构的各向异性，我们测量了作为平行和垂直于视线的分离函数的相关函数。我们在各向异性相关函数中发现了轻微的重子特征信号，即，一个“重子脊”对应于球平均相关函数中的重子声峰，这已经使用相同的样本报道过。重子脊主要是一个球形结构，在共动坐标系中有一个已知的半径。它使我们能够将红移失真效应划分为动力学和几何分量，并提供对宇宙学参数（包括暗能量状态方程）的进一步约束。在平坦Λ宇宙学的假设下，当我们使用40 < s < 200 h−1 Mpc的各向异性相关函数的整体形状（包括重子声学振荡的尺度）时，我们发现最佳拟合值Ωm = 0.218−0.037+0.047和ΩB = 0.047 ± 0.016（68% CL）。当采用Ω bh 2 = 0.024的附加假设时，我们得到ΩDE = 0.770−0.040+0.051和w = − 0.93−0.35+0.45。这些限制估计只有从我们的数据的各向异性相关函数，他们同意相当不错的值都从宇宙微波背景（CMB）的各向异性和其他互补统计使用LRG样本。由于CMB在3年WMAP结果之前，我们对这些参数给出了更强的约束。
We study the large-scale anisotropic two-point correlation function using 46,760 luminous red galaxies at redshifts 0.16-0.47 from the Sloan Digital Sky Survey. We measure the correlation function as a function of separations parallel and perpendicular to the line of sight in order to take account of anisotropy of the large-scale structure in redshift space. We find a slight signal of baryonic features in the anisotropic correlation function, i.e., a “baryon ridge” corresponding to a baryon acoustic peak in the spherically averaged correlation function, which has already been reported using the same sample. The baryon ridge has primarily a spherical structure with a known radius in comoving coordinates. It enables us to divide the redshift distortion effects into dynamical and geometrical components and provides further constraints on cosmological parameters, including the dark energy equation-of-state. With an assumption of a flat Λ cosmology, we find the best-fit values of Ωm = 0.218−0.037+0.047 and Ωb = 0.047 ± 0.016 (68% CL) when we use the overall shape of the anisotropic correlation function of 40 < s < 200 h−1 Mpc including a scale of baryon acoustic oscillations. When an additional assumption of Ωbh2 = 0.024 is adopted, we obtain ΩDE = 0.770−0.040+0.051 and w = − 0.93−0.35+0.45. These constraints are estimated only from our data of the anisotropic correlation function, and they agree quite well with values both from the cosmic microwave background (CMB) anisotropies and from other complementary statistics using the LRG sample. With the CMB prior from the 3 year WMAP results, we give stronger constraints on those parameters.