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arXiv 0908.2598astro-ph.CO
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SDSS LRG样品的重子声学特征和大尺度聚类

The Baryonic Acoustic Feature and Large-Scale Clustering in the SDSS LRG Sample

Eyal A. Kazin, Michael R. Blanton, Roman Scoccimarro, Cameron K. McBride, Andreas A. Berlind, Neta A. Bahcall, Jon Brinkmann, Paul Czarapata, Joshua A. Frieman,… 展开作者

Eyal A. Kazin, Michael R. Blanton, Roman Scoccimarro, Cameron K. McBride, Andreas A. Berlind, Neta A. Bahcall, Jon Brinkmann, Paul Czarapata, Joshua A. Frieman, Stephan M. Kent, Donald P. Schneider, Alexander S. Szalay

摘要:

我们使用最终的数据发布(DR 7; 105,831个LRG在0.16<z<0.47之间)在大尺度(60<s<400 Mpc/h)下检查了斯隆数字巡天(SDSS)亮红星系样本(LRG)的关联函数。利用模拟星表,我们证明了在1.5σ水平上,所观测到的重子声峰和大尺度信号与LCDM是一致的。在155<s<200 Mpc/h的信号相对于理论预期往往是高的;这种轻微的偏差可以归因于LRG的明亮子样本。将数据拟合到一个非线性的、红移空间的、基于模板的模型中,当拟合范围为60<s<150 Mpc/h时,我们将峰位置限制在s_p=103.6+3.6-2.4 Mpc/h(1σ的不确定度从模拟中测量)。在考虑了物质成团非线性、红移畸变和星系成团偏差后,这个红移空间距离s_p与同动声视界尺度r_s有关。模拟星表显示,DR 7大小的样本不具有可识别峰的概率至少为10%。作为对基准宇宙学的一致性检验,我们利用观测到的s_p来获得相对于声学尺度的距离D_V=[(1+z)^2D_A^2cz/H(z)]^(1/3)。r_s/D_V(z=0.278)=0.1394 ± 0.0049。这一结果与Percival et. al(2009),他研究了大致相同的数据集,但使用了功率谱。与文献中的其他测定结果进行比较也非常一致。我们已经测试了我们的结果对电池的可能的系统性影响,发现所有的影响都小于我们估计的样本方差。

英文摘要:

We examine the correlation function ξof the Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy sample (LRG) at large scales (60<s<400 Mpc/h) using the final data release (DR7; 105,831 LRGs between 0.16<z<0.47). Using mock catalogs, we demonstrate that the observed baryonic acoustic peak and larger scale signal are consistent with LCDM at the 1.5σlevel. The signal at 155<s<200 Mpc/h tends to be high relative to theoretical expectations; this slight deviation can be attributed to a bright subsample of the LRGs. Fitting data to a non-linear, redshift-space, template based-model, we constrain the peak position at s_p=103.6+3.6-2.4 Mpc/h when fitting the range 60<s<150 Mpc/h (1σuncertainties measured from the mocks. This redshift-space distance s_p is related to the comoving sound horizon scale r_s after taking into account matter clustering non-linearities, redshift distortions and galaxy clustering bias. Mock catalogs show that the probability that a DR7-sized sample would not have an identifiable peak is at least 10%. As a consistency check of a fiducial cosmology, we use the observed s_p to obtain the distance D_V=[(1+z)^2D_A^2cz/H(z)]^(1/3) relative to the acoustic scale. We find r_s/D_V(z=0.278)=0.1394+-0.0049. This result is in excellent agreement with Percival et. al (2009), who examine roughly the same data set, but using the power spectrum. Comparison with other determinations in the literature are also in very good agreement. We have tested our results against a battery of possible systematic effects, finding all effects are smaller than our estimated sample variance.

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