论文标题
部分可观测时空混沌系统的无模型预测
Assessing theoretical uncertainties for cosmological constraints from weak lensing surveys
论文作者
论文摘要
$ $弱重力镜头是一种强大的探针，用于限制标准宇宙学模型及其扩展。随着当前和即将进行的调查的统计精度增强，需要对弱透镜统计的高精度预测，以限制理论不确定性对宇宙学参数约束的影响。为此，我们基于广泛使用的拟合功能（$ \ texttt {mead} $和$ \ texttt {rev-halofit} $）的理论预测，对非线性物质和弱透镜功率谱的理论预测进行比较。 $ \ texttt {baccoemulator} $和$ \ texttt {cosmicemulator} $）和n-body模拟（$ \ texttt {pkdgrav3} $）。我们考虑$λ\ texttt {cdm} $和$ \ texttt {wcdm} $模型的预测约束。我们研究了对约束及其对假定处方的依赖的相对偏见。假设$λ\ texttt {CDM} $宇宙学，我们发现$ S_8 $参数的相对协议在上述预测变量之间的类似III的调查的$0.2-0.3σ$之间。对于类似IV阶段的调查，该协议变为$1.4-3.0σ$。在$ \ texttt {wcdm} $方案中，我们发现了更广泛的$ s_8 $约束，并分别为$0.18-0.26σ$和$0.7-1.7σ$的协议分别用于第三阶段和第四阶段调查。因此，上述预测因子的准确性似乎足以进行III期调查，而拟合功能将需要改进未来的IV级弱透镜调查。此外，我们发现，在拟合功能中，$ \ texttt {mead} $提供了与模拟器的最佳协议。我们讨论了这些发现对未来弱透镜调查的准备的含义。
$ $Weak gravitational lensing is a powerful probe which is used to constrain the standard cosmological model and its extensions. With the enhanced statistical precision of current and upcoming surveys, high accuracy predictions for weak lensing statistics are needed to limit the impact of theoretical uncertainties on cosmological parameter constraints. For this purpose, we present a comparison of the theoretical predictions for the nonlinear matter and weak lensing power spectra, based on the widely used fitting functions ($\texttt{mead}$ and $\texttt{rev-halofit}$), emulators ($\texttt{EuclidEmulator}$, $\texttt{EuclidEmulator2}$, $\texttt{BaccoEmulator}$ and $\texttt{CosmicEmulator}$) and N-body simulations ($\texttt{Pkdgrav3}$). We consider the forecasted constraints on the $Λ\texttt{CDM}$ and $\texttt{wCDM}$ models from weak lensing for stage III and stage IV surveys. We study the relative bias on the constraints and their dependence on the assumed prescriptions. Assuming a $Λ\texttt{CDM}$ cosmology, we find that the relative agreement on the $S_8$ parameter is between $0.2-0.3σ$ for a stage III-like survey between the above predictors. For a stage IV-like survey the agreement becomes $1.4-3.0σ$. In the $\texttt{wCDM}$ scenario, we find broader $S_8$ constraints, and agreements of $0.18-0.26σ$ and $0.7-1.7σ$ for stage III and stage IV surveys, respectively. The accuracies of the above predictors therefore appear adequate for stage III surveys, while the fitting functions would need improvements for future stage IV weak lensing surveys. Furthermore, we find that, of the fitting functions, $\texttt{mead}$ provides the best agreement with the emulators. We discuss the implication of these findings for the preparation of the future weak lensing surveys.
