What is the best way to measure baryonic acoustic oscillations
What is the best way to measure baryonic acoustic oscillations
复制标题
测量重子声振荡的最佳方法是什么
DOI：
10.1111/j.1365-2966.2008.13769.x
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发表时间：
2008
影响因子：
4.8
通讯作者：
Uk
中科院分区：
文献类型：
--
作者：
A. Sánchez;C. Baugh;Raul Angulo Mpe;Garching;Germany;Icc;Durham;Uk
重组之前重子光子流体中的振荡在功率谱和物质波动的相关函数上留下了不同的特征。已提出使用星系巡天来测量这些特征作为确定暗能量状态方程的手段。实现竞争约束所需的精度要求对改变重子声振荡（BAO）印记的系统效应有非常好的理解。我们使用 50 个非常大体积的 N 体模拟来研究两点相关函数中的 BAO 特征。即使在考虑任何动态或统计效应之前，BAO 凸点的位置也不符合未来测量所需精度水平的声层尺度。因此，需要对相关函数进行仔细建模，以提取大规模编码的宇宙学信息。我们发现相关函数比功率谱受尺度相关效应的影响更小。我们证明了 Crocce 和 Scoccimarro (2008) 提出的基于重正化微扰理论的相关函数模型，给出了暗能量状态方程的基本无偏测量。这意味着除了 BAO 峰值的形式之外，来自相关函数的大尺度形状的信息还可用于提供对宇宙学参数的稳健约束。因此，与使用功率谱时所需的更保守的方法（即需要丢弃幅度和长波长形状信息）相比，相关函数对距离尺度提供了更好的约束（误差小 50%，没有系统偏差）。
Oscillations in the baryon-photon fluid prior to recombination imprint different signatures on the power spectrum and correlation function of matter fluctuations. The measurement of these features using galaxy surveys has been proposed as means to determine the equation of state of the dark energy. The accuracy required to achieve competitive constraints demands an extremely good understanding of systematic effects which change the baryonic acoustic oscillation (BAO) imprint. We use 50 very large volume N-body simulations to investigate the BAO signature in the two-point correlation function. The location of the BAO bump does not correspond to the sound horizon scale at the level of accuracy required by future measurements, even before any dynamical or statistical effects are considered. Careful modelling of the correlation function is therefore required to extract the cosmological information encoded on large scales. We find that the correlation function is less affected by scale dependent effects than the power spectrum. We show that a model for the correlation function proposed by Crocce & Scoccimarro (2008), based on renormalised perturbation theory, gives an essentially unbiased measurement of the dark energy equation of state. This means that information from the large scale shape of the correlation function, in addition to the form of the BAO peak, can be used to provide robust constraints on cosmological parameters. The correlation function therefore provides a better constraint on the distance scale (� 50% smaller errors with no systematic bias) than the more conservative approach required when using the power spectrum (i.e. which requires amplitude and long wavelength shape information to be discarded).