REVISING THE HALOFIT MODEL FOR THE NONLINEAR MATTER POWER SPECTRUM
REVISING THE HALOFIT MODEL FOR THE NONLINEAR MATTER POWER SPECTRUM
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DOI：
10.1088/0004-637x/761/2/152
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
R. Takahashi;Masanori Sato;T. Nishimichi;A. Taruya;M. Oguri
中科院分区：
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作者：
R. Takahashi;Masanori Sato;T. Nishimichi;A. Taruya;M. Oguri
基于一套最先进的高分辨率n体模拟，我们重新审视了所谓的halofit模型，作为非线性物质功率谱的精确拟合公式。虽然halofit模型经常被用作标准的宇宙学工具来预测由冷暗物质主导的宇宙中的非线性物质功率谱，但其精度受到用于确定拟合参数的n体模拟的低分辨率的限制，这表明在未来的宇宙学研究中有必要改进小尺度拟合公式。我们围绕威尔金森微波各向异性探测器最适合的宇宙学参数（1年、3年、5年和7年的结果）对16个宇宙学模型进行了高分辨率n体模拟，包括具有恒定状态方程的暗能量模型。利用模拟结果对halofit模型的拟合参数进行重新标定，以再现n体模拟的小尺度功率谱，同时保持大尺度精度。修正后的拟合公式提供了在红移0≤z≤10的宽波数范围内（k≤30 h Mpc−1）的非线性物质功率谱的准确预测，在0≤z≤10的k≤1 h Mpc−1的精度为5%，在0≤z≤3的1≤k≤10 h Mpc−1的精度为10%。讨论了改进的halofit模型对弱透镜功率谱和相关函数的影响，表明改进的模型能较好地再现光线追踪仿真结果。
Based on a suite of state-of-the-art high-resolution N-body simulations, we revisit the so-called halofit model as an accurate fitting formula for the nonlinear matter power spectrum. While the halofit model has frequently been used as a standard cosmological tool to predict the nonlinear matter power spectrum in a universe dominated by cold dark matter, its precision has been limited by the low resolution of N-body simulations used to determine the fitting parameters, suggesting the necessity of an improved fitting formula at small scales for future cosmological studies. We run high-resolution N-body simulations for 16 cosmological models around the Wilkinson Microwave Anisotropy Probe best-fit cosmological parameters (one-, three-, five-, and seven-year results), including dark energy models with a constant equation of state. The simulation results are used to re-calibrate the fitting parameters of the halofit model so as to reproduce small-scale power spectra of the N-body simulations, while keeping the precision at large scales. The revised fitting formula provides an accurate prediction of the nonlinear matter power spectrum in a wide range of wavenumbers (k ⩽ 30 h Mpc−1) at redshifts 0 ⩽ z ⩽ 10, with 5% precision for k ⩽ 1 h Mpc−1 at 0 ⩽ z ⩽ 10 and 10% for 1 ⩽ k ⩽ 10 h Mpc−1 at 0 ⩽ z ⩽ 3. We discuss the impact of the improved halofit model on weak-lensing power spectra and correlation functions, and show that the improved model better reproduces ray-tracing simulation results.