A 2 per cent distance to $z$=0.35 by reconstructing baryon acoustic oscillations - I. Methods and application to the Sloan Digital Sky Survey
A 2 per cent distance to $z$=0.35 by reconstructing baryon acoustic oscillations - I. Methods and application to the Sloan Digital Sky Survey
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DOI：
10.1111/j.1365-2966.2012.21888.x
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发表时间：
2012-02
影响因子：
4.8
通讯作者：
N. Padmanabhan;Xiaoying Xu;D. Eisenstein;R. Scalzo;A. Cuesta;K. Mehta;E. Kazin
中科院分区：
文献类型：
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作者：
N. Padmanabhan;Xiaoying Xu;D. Eisenstein;R. Scalzo;A. Cuesta;K. Mehta;E. Kazin
我们首次将密度场重建应用于星系探测，以消除由于非线性引力演化而产生的重子声振荡(BAO)特征的平滑，从而可能提高距离测量的精度。我们将重建技术应用于来自斯隆数字天空调查(SDSS)数据发布7(DR7)发光红色星系(LRG)样本的星系团，增强了Bao特征，实现了1.9%的距离测量，z=0.35。我们更新了Eisenstein等人的重建算法。以考虑测量几何以及红移空间扭曲的影响，并在160个LasDamas模拟中进行验证。我们证明了重建增强了角度平均星系关联函数中的BaO特征，将非线性平滑尺度ΣnL从8.1mpc h−1减小到4.4Mpc h Mpc 1。重建还显著地减少了BaO尺度上红移空间扭曲的影响，使关联函数各向同性。这种锐化的Bao特征产生了公正的距离估计(0.2%)，并将离散度从3.3%降至2.1%。我们证明了这些结果对各种重建参数的稳健性，包括平滑尺度、星系偏差和线性增长率。将该重建算法应用于SDSS LRG DR7样本，将BAO特征在这些数据中的重要性从重建前的3.3σ提高到重建后的4.2σ。我们估计相对距离标度dV/rS=0.358.88±0.17，其中rS是声界，是角直径距离DA和哈勃参数H的组合。假设声界为154.25 mpc，这就转化为距离测量dv(z=0.35)=1.356±0.025 gpc。我们发现，重建将DR7样本的距离误差从3.5%降低到1.9%，相当于三倍于SDSS体积的调查。
We present the first application to density field reconstruction to a galaxy survey to undo the smoothing of the baryon acoustic oscillation (BAO) feature due to non-linear gravitational evolution and thereby improve the precision of the distance measurements possible. We apply the reconstruction technique to the clustering of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) luminous red galaxy (LRG) sample, sharpening the BAO feature and achieving a 1.9 per cent measurement of the distance to z = 0.35. We update the reconstruction algorithm of Eisenstein et al. to account for the effects of survey geometry as well as redshift-space distortions and validate it on 160 LasDamas simulations. We demonstrate that reconstruction sharpens the BAO feature in the angle averaged galaxy correlation function, reducing the non-linear smoothing scale Σnl from 8.1 to 4.4 Mpc h−1. Reconstruction also significantly reduces the effects of redshift-space distortions at the BAO scale, isotropizing the correlation function. This sharpened BAO feature yields an unbiased distance estimate (<0.2 per cent) and reduces the scatter from 3.3 to 2.1 per cent. We demonstrate the robustness of these results to the various reconstruction parameters, including the smoothing scale, the galaxy bias and the linear growth rate. Applying this reconstruction algorithm to the SDSS LRG DR7 sample improves the significance of the BAO feature in these data from 3.3σ for the unreconstructed correlation function to 4.2σ after reconstruction. We estimate a relative distance scale DV/rs to z = 0.35 of 8.88 ± 0.17, where rs is the sound horizon and is a combination of the angular diameter distance DA and Hubble parameter H. Assuming a sound horizon of 154.25 Mpc, this translates into a distance measurement DV(z = 0.35) = 1.356 ± 0.025 Gpc. We find that reconstruction reduces the distance error in the DR7 sample from 3.5 to 1.9 per cent, equivalent to a survey with three times the volume of SDSS.