arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1306.6660astro-ph.CO
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非线性动力学如何影响重子声学振荡?

How does non-linear dynamics affect the baryon acoustic oscillation?

Naonori S. Sugiyama, David N. Spergel

摘要:

通过将暗物质微扰分解为短、长两种模式,研究了重子声学振荡在功率谱和关联函数中的非线性行为。暗物质涨落的演化可以描述为长波长位移矢量作用于非线性增长的短波长物质扰动所引起的全局坐标变换。利用这一特性,我们研究了在标准微扰理论中高$k$解的著名消除。虽然标准的扰动理论自然地满足高$k$解决方案的取消,最近提出的一些改进的扰动理论不保证取消。我们表明,这种取消澄清成功的标准微扰理论在2圈的顺序在描述的振幅的非线性功率谱,即使在高$k$ regions.We提出了一个扩展的标准2圈水平微扰理论模型的非线性功率谱,更准确地模拟非线性演化的重子声学振荡比标准微扰理论。该模型由简单直观的两部分组成:不含重子声学振荡的平滑功率谱的非线性演化和由于暗物质的大尺度速度和由于暗物质粒子间的引力引起的重子声学振荡的非线性演化.我们的扩展模型预测的重子声学振荡峰在$z=0.35$的平滑参数为$\sim 7.7\ {\rm Mpc}/h$,并描述了小的非线性位移的峰值位置,由于星系的随机运动。

英文摘要:

We study the non-linear behavior of the baryon acoustic oscillation in the power spectrum and the correlation function by decomposing the dark matter perturbations into the short- and long-wavelength modes. The evolution of the dark matter fluctuations can be described as a global coordinate transformation caused by the long-wavelength displacement vector acting on short-wavelength matter perturbation undergoing non-linear growth. Using this feature, we investigate the well known cancellation of the high-$k$ solutions in the standard perturbation theory. While the standard perturbation theory naturally satisfies the cancellation of the high-$k$ solutions, some of the recently proposed improved perturbation theories do not guarantee the cancellation. We show that this cancellation clarifies the success of the standard perturbation theory at the 2-loop order in describing the amplitude of the non-linear power spectrum even at high-$k$ regions.We propose an extension of the standard 2-loop level perturbation theory model of the non-linear power spectrum that more accurately models the non-linear evolution of the baryon acoustic oscillation than the standard perturbation theory. The model consists of simple and intuitive parts: the non-linear evolution of the smoothed power spectrum without the baryon acoustic oscillations and the non-linear evolution of the baryon acoustic oscillations due to the large-scale velocity of dark matter and due to the gravitational attraction between dark matter particles. Our extended model predicts the smoothing parameter of the baryon acoustic oscillation peak at $z=0.35$ as $\sim 7.7\ {\rm Mpc}/h$ and describes the small non-linear shift in the peak position due to the galaxy random motions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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