The Nonlinear Matter Power Spectrum
The Nonlinear Matter Power Spectrum
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DOI：
10.1086/519440
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发表时间：
2006-10
期刊：
影响因子：
--
通讯作者：
Zhaoming Ma
中科院分区：
文献类型：
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作者：
Zhaoming Ma
我们修改了Anatoly Klypin和Jon Holtzman开发的公共PM程序，以模拟具有任意初始功率谱和暗能量状态方程的宇宙学。利用这一工具，我们对物质功率谱进行了以下研究。在初始功率谱中，当k ~ 0.2hMpc-1处出现一个人工尖峰时，发现该尖峰的位置并不因非线性演化而发生移动。在0.02%的水平上的移位的上限是通过使用幂律加高斯拟合峰值的局部功率谱来实现的。我们还发现，在线性功率谱中的峰值的存在会均匀地提高在所有尺度上的非线性功率。这与HKLM标度关系的预测相反，但与晕模型大致一致。我们今天构建了具有相同线性功率谱但不同线性增长历史的暗能量模型。我们证明了它们的非线性功率谱在过去相应的线性功率谱的最大偏差的水平上不同。同样，两个构造的暗能量模型具有相同的增长历史的结果一致的非线性功率谱。这是暗示，而不是证明，线性功率谱与线性增长历史一起唯一地确定非线性功率谱。基于这些结果，我们建议在下一代非线性功率谱拟合公式中加入线性增长历史。最后，我们评论现有的拟合公式的精度时，适用于暗能量模型参数的w 0和wa。
We modify the public PM code developed by Anatoly Klypin and Jon Holtzman to simulate cosmologies with arbitrary initial power spectra and the equation of state of dark energy. With this tool in hand, we perform the following studies on the matter power spectrum. With an artificial sharp peak at k ~ 0.2 h Mpc-1 in the initial power spectrum, we find that the position of the peak is not shifted by nonlinear evolution. An upper limit of the shift at the level of 0.02% is achieved by fitting the power spectrum local to the peak using a power law plus a Gaussian. We also find that the existence of a peak in the linear power spectrum would boost the nonlinear power at all scales evenly. This is contrary to what the HKLM scaling relation predicts, but roughly consistent with that of the halo model. We construct dark energy models with the same linear power spectra today but different linear growth histories. We demonstrate that their nonlinear power spectra differ at the level of the maximum deviation of the corresponding linear power spectra in the past. Similarly, two constructed dark energy models with the same growth histories result in consistent nonlinear power spectra. This is hinting, not a proof, that the linear power spectrum together with linear growth history uniquely determine the nonlinear power spectrum. Based on these results, we propose that linear growth history be included in the next-generation fitting formulae of the nonlinear power spectrum. Finally, we comment on the precision of existing fitting formulae when applied to dark energy models parametrized by w0 and wa.