What is the best way to measure baryonic acoustic oscillations?
Ariel G. Sanchez, Carlton M. Baugh, Raul Angulo
备注：
25 pages, 18 figures; replaced with version accepted for publication in MNRAS. Extended analysis by including a model of the correlation function based on renormalized perturbation theory
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).
Perturbation Theory Reloaded: Analytical Calculation of Non-linearity in Baryonic Oscillations in the Real Space Matter Power Spectrum
我们比较了在1<z<6时，从三阶微扰理论解析计算的真实空间中的非线性物质功率谱与N体模拟。我们发现，在弱非线性区域中，微扰理论预测与模拟结果的一致性优于1%的准确度，其中无量纲功率谱Δ 2（k）=k^3P（k）/2 pi ^2，它近似地给出了给定k下物质密度场的方差，小于0.4。虽然重子声学振荡特征在z>1的弱非线性区域中保持，但振荡的形状与线性理论预测不同。尽管如此，我们的结果表明，人们可以几乎精确地纠正非线性引起的失真。我们还发现，微扰理论，它不包含任何自由参数，提供了一个显着更好的适合模拟比传统的方法基于经验拟合函数模拟。未来的工作将包括微扰理论计算的非线性红移空间扭曲和晕偏置的弱非线性制度。
Probing dark energy with baryonic oscillations and future radio surveys of neutral Hydrogen
目前的调查可能即将测量星系功率谱中的重子振荡，这些振荡清晰地印在宇宙微波背景上。最近有人提出，这些振荡允许一个“标准尺”的方法探测状态方程的暗能量。在本文中，我们提出了一个新的计算星系的数量，未来的射电望远镜将发现在调查的天空中的中性氢（HI）。我们估计，如果标准标尺法被应用于此类调查，可能出现的统计误差。我们强调在我们的计算中的不确定性，并查明未来的HI调查的最重要的功能，如果他们是通过重子振荡提供新的约束暗能量。未来射电望远镜的设计要求具有大的带宽（表征为β $, the ratio of the instantaneous bandwidth to the bandwidth required by survey) and to have the widest instantaneous (1.4 GHz) field of view ($ FOV $) possible. Given the expected sensitivity of a future Square Kilometre Array (SKA), given that half of its collecting area will be concentrated in a core of diameter $ \sim 5 ~ \rm km $, and given a reasonable surve…
Acoustic oscillations in the SDSS Luminous Red Galaxy sample power spectrum
我们计算了斯隆数字巡天（SDSS）亮红星系（LRG）样本的红移空间功率谱，发现了一系列声学特征的证据，这些特征的尺度可达~0.25 h Mpc^{-1}。这相当于9。CMB角功率谱中的峰值。导出的声学标度为（107.8 +- 4.3）h^{-1}Mpc（k < 0.2 h Mpc^{-1}），与"和谐“模型预测以及Eisenstein等人通过分析空间两点关联函数确定的声学标度非常一致。（2005年）。这不仅是一个独立的确认爱森斯坦等人。（2005）用不同方法和软件得到的结果，而且根据我们的知识，第一次测定了SDSS LRG样品的功率谱。用光滑三次样条模型拟合观测的带功率，计算两点关联函数，并与直接测定的结果进行比较，证明了结果的一致性。
