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arXiv 1206.6732astro-ph.CO
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用重子声学振荡测量SDSS DR7 LRG在z=0.35处的D_A和H

Measuring D_A and H at z=0.35 from the SDSS DR7 LRGs using baryon acoustic oscillations

Xiaoying Xu, Antonio J. Cuesta, Nikhil Padmanabhan, Daniel J. Eisenstein, Cameron K. McBride

摘要:

利用Sloan数字巡天(SDSS)数据发布7(DR 7)的亮红星系(LRG)样本中星系团分布中的重子声学振荡(BAO)信号的各向异性,测量了角直径距离DA(z)和z=0.35的哈勃参数H(z)。我们的工作是第一个应用密度场重建的声学峰值的各向异性分析。重建部分消除了非线性演化和红移空间失真的影响,以便锐化声学信号。我们提出了各向异性BAO信号背后的理论框架,并详细介绍了我们用于从数据中提取该信号的拟合模型。我们的方法仅关注声学峰值各向异性,而不是来自宽带功率的更多模型依赖的各向异性信息。我们测试了我们的分析方法的鲁棒性160 LasDamas DR 7模拟目录,发现我们的模型在测量BAO各向异性的~0.2%的水平是无偏的。重建后,我们测得D_A(z=0.35)=1050+/-38Mpc,H(z=0.35)=84.4+/-7.0km/s/Mpc,假设声视界r_s= 152.76Mpc。注意,这些测量值与0.58的相关系数相关。这表示相对于重建前的情况,D_A上的误差改进了1.4倍;对于H,看到了1.2倍的改进。

英文摘要:

We present measurements of the angular diameter distance D_A(z) and the Hubble parameter H(z) at z=0.35 using the anisotropy of the baryon acoustic oscillation (BAO) signal measured in the galaxy clustering distribution of the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) Luminous Red Galaxies (LRG) sample. Our work is the first to apply density-field reconstruction to an anisotropic analysis of the acoustic peak. Reconstruction partially removes the effects of non-linear evolution and redshift-space distortions in order to sharpen the acoustic signal. We present the theoretical framework behind the anisotropic BAO signal and give a detailed account of the fitting model we use to extract this signal from the data. Our method focuses only on the acoustic peak anisotropy, rather than the more model-dependent anisotropic information from the broadband power. We test the robustness of our analysis methods on 160 LasDamas DR7 mock catalogues and find that our models are unbiased at the ~0.2% level in measuring the BAO anisotropy. After reconstruction we measure D_A(z=0.35)=1050+/-38 Mpc and H(z=0.35)=84.4+/-7.0 km/s/Mpc assuming a sound horizon of r_s=152.76 Mpc. Note that these measurements are correlated with a correlation coefficient of 0.58. This represents a factor of 1.4 improvement in the error on D_A relative to the pre-reconstruction case; a factor of 1.2 improvement is seen for H.

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