DEUS-PUR $Cosmo$模拟中物质功率谱协方差的宇宙学模型参数依赖性
Cosmological Model Parameter Dependence of the Matter Power Spectrum Covariance from the DEUS-PUR $Cosmo$ Simulations
摘要：
未来的星系巡天将在前所未有的尺度和红移范围内提供物质功率谱的精确测量。这些数据的分析将需要一个精确的模型的物质密度场的非线性的印记。特别是，这些诱导非高斯贡献的数据协方差，需要适当考虑实现无偏宇宙学参数推断分析。在这里，我们研究的宇宙学依赖的物质功率谱协方差使用一个专用的N体模拟套件，暗能量宇宙模拟-平行宇宙的平行宇宙的（DEUS-PUR）{ \it Cosmo}。这些包括512实现10个不同的宇宙学，我们改变物质密度$Ω_m$，密度波动的幅度$σ_8$，减少哈勃参数$h$和一个恒定的暗能量状态方程$w$约$10\%$。我们使用这些数据来评估一阶和二阶导数的功率谱协方差相对于基准$Λ$ CDM宇宙学。我们发现，变化可以大到$150\%$取决于规模，红移和模型参数考虑。通过执行Fisher矩阵分析，我们探讨了不同的选择在建模的协方差的宇宙学依赖的影响。我们的研究结果表明，固定协方差的基准宇宙学可以显着影响恢复的参数误差和建模的宇宙学依赖的方差，同时保持相关系数固定可以减轻这种影响。
英文摘要：
Future galaxy surveys will provide accurate measurements of the matter power spectrum across an unprecedented range of scales and redshifts. The analysis of these data will require one to accurately model the imprint of non-linearities of the matter density field. In particular, these induce a non-Gaussian contribution to the data covariance that needs to be properly taken into account to realise unbiased cosmological parameter inference analyses. Here, we study the cosmological dependence of the matter power spectrum covariance using a dedicated suite of N-body simulations, the Dark Energy Universe Simulation - Parallel Universe Runs (DEUS-PUR) {\it Cosmo}. These consist of 512 realizations for 10 different cosmologies where we vary the matter density $Ω_m$, the amplitude of density fluctuations $σ_8$, the reduced Hubble parameter $h$ and a constant dark energy equation of state $w$ by approximately $10\%$. We use these data to evaluate the first and second derivatives of the power spectrum covariance with respect to a fiducial $Λ$CDM cosmology. We find that the variations can be as large as $150\%$ depending on the scale, redshift and model parameter considered. By performing a Fisher matrix analysis we explore the impact of different choices in modelling the cosmological dependence of the covariance. Our results suggest that fixing the covariance to a fiducial cosmology can significantly affect the recovered parameter errors and that modelling the cosmological dependence of the variance while keeping the correlation coefficient fixed can alleviate the impact of this effect.
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