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arXiv 1006.0699astro-ph.COgr-qc
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二维重子声学振荡:微扰理论模拟红移空间功率谱

Baryon Acoustic Oscillations in 2D: Modeling Redshift-space Power Spectrum from Perturbation Theory

Atsushi Taruya, Takahiro Nishimichi, Shun Saito

摘要:

提出了一种改进的红移空间物质功率谱公式,该公式适当考虑了非线性引力成团和红移畸变,这对精确模拟重子声学振荡(BAO)具有重要意义.与文献中常用的唯象红移畸变模型相反,新模型包括了密度场和速度场之间的非线性耦合所引起的修正,这种非线性耦合与红移畸变的两种竞争效应有关,即,皇帝和上帝之指的效果。基于改进的引力团簇微扰理论的处理,我们比较了我们的模型预测与N-体模拟的四极和四极功率谱,并取得了很好的协议的尺度上的BAO。基于Fisher矩阵理论,我们还研究了红移空间功率谱对约束暗能量和修正引力的潜在影响。我们发现,现有的红移畸变唯象模型对角直径距离和哈勃参数的测量产生了1~ 2%的系统误差,对增长率参数的测量产生了~ 5%的系统误差,这将对未来的星系巡天观测产生不可忽视的影响。因此,正确地模拟红移失真是必不可少的,包括非线性校正的红移空间功率谱的新处方可以用作各向异性BAO的准确的理论模板。

英文摘要:

We present an improved prescription for matter power spectrum in redshift space taking a proper account of both the non-linear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the non-linear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with monopole and quadrupole power spectra of N-body simulations, and an excellent agreement is achieved over the scales of BAOs. Potential impacts on constraining dark energy and modified gravity from the redshift-space power spectrum are also investigated based on the Fisher-matrix formalism. We find that the existing phenomenological models of redshift distortion produce a systematic error on measurements of the angular diameter distance and Hubble parameter by 1~2%, and the growth rate parameter by ~5%, which would become non-negligible for future galaxy surveys. Correctly modeling redshift distortion is thus essential, and the new prescription of redshift-space power spectrum including the non-linear corrections can be used as an accurate theoretical template for anisotropic BAOs.

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