论文标题
不等的物质功率谱：对弱透镜可观察力的影响
The unequal-time matter power spectrum: impact on weak lensing observables
论文作者
论文摘要
我们研究了共同近似对弱透镜功率谱的影响：在红移而不是在积分中使用单位物质功率谱。我们将其与紧密连接的Limber的近似相关。我们在标准扰动理论和有效的现场理论中得出了一环的不等时间功率谱，以处理非线性物理。我们比较了这些形式主义，并得出结论，使用有效的现场理论破坏了较大尺度的不等时间功率谱。作为替代方案，我们介绍了中点近似。我们还首次提供了基于Quijote仿真的有效场理论对抗的时间演变的拟合函数。然后，我们使用一系列方法来计算角功率谱：Limber的近似值以及几何和中点近似值。我们将结果与使用不等的时间功率谱在所有角度尺度上进行的确切计算进行比较。我们使用DES Y1和类似LSST的红移分布进行分析。我们发现，在弱透镜中使用Limber的近似值与大角度分离上的角功率谱的确切计算不同，$ \ ell <10 $。即使此偏差为订单$ 2 \％$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $，但我们发现对星系聚类和银河系镜头镜头的效果最大。我们表明，这不仅对于即将进行的星系调查，而且对于当前数据（例如DES Y1）都是如此。最后，我们将管道和分析作为一个称为“ Ungualpy”的Python包上的公共可用。
We investigate the impact of a common approximation on weak lensing power spectra: the use of single-epoch matter power spectra in integrals over redshift. We disentangle this from the closely connected Limber's approximation. We derive the unequal-time matter power spectrum at one-loop in standard perturbation theory and effective field theory to deal with non-linear physics. We compare these formalisms and conclude that the unequal-time power spectrum using effective field theory breaks for larger scales. As an alternative, we introduce the midpoint approximation. We also provide, for the first time, a fitting function for the time evolution of the effective field theory counterterms based on the Quijote simulations. Then we compute the angular power spectrum using a range of approaches: the Limber's approximation, and the geometric and midpoint approximations. We compare our results with the exact calculation at all angular scales using the unequal-time power spectrum. We use DES Y1 and LSST-like redshift distributions for our analysis. We find that the use of the Limber's approximation in weak lensing diverges from the exact calculation of the angular power spectrum on large-angle separations, $\ell < 10$. Even though this deviation is of order $2\%$ maximum for cosmic lensing, we find the biggest effect for galaxy clustering and galaxy-galaxy lensing. We show that not only is this true for upcoming galaxy surveys, but also for current data such as DES Y1. Finally, we make our pipeline and analysis publicly available as a Python package called unequalpy.
