A revised density split statistic model for general filters
A revised density split statistic model for general filters
复制标题
通用滤波器修正的密度分裂统计模型
DOI：
10.1051/0004-6361/202141628
复制
发表时间：
2022
影响因子：
6.5
通讯作者：
Burger P
中科院分区：
文献类型：
--
作者：
Burger P
在弱引力透镜下研究宇宙大尺度结构的统计特性是当前和即将进行的几个星系调查的主要目标。弱透镜对宇宙学参数的约束可以通过考虑二阶剪切相关函数或功率谱以外的统计来增强。高密度分割统计（DSS）就是这样一种高阶探测方法，它在观测数据中被证明是成功的，它分析了根据前景星系密度分类的点周围的平均剪切剖面。在本文中，我们推广了最精确的DSS模型，以允许广泛的角滤波函数用于不同局部密度区域的分类。这种方法的动机是早期的研究结果表明，与标准的礼帽案例相比，优化的过滤器可以对模型参数提供更严格的约束。方法在之前的DSS模型中，我们建立了大偏差理论方法及其近似来模拟物质密度概率分布函数，并建立了密度场高阶矩的微扰计算。新颖的添加依赖于这些以前使用的计算的泛化，以允许一般的过滤函数，并在几组数值模拟中得到验证。结果表明，修正后的模型对许多滤波器的选择都能很好地拟合模拟测量结果，与当前弱透镜调查的统计精度相比，其剩余系统偏移较小。然而，通过使用一种简单的校准方法和马尔可夫链蒙特卡罗分析，我们研究了DSS对宇宙学参数的预期灵敏度，并找到了与常用的两点宇宙剪切测量相当的无偏结果和约束。因此，我们的DSS模型可以用于当前宇宙剪切数据的竞争性分析，尽管它可能需要在即将到来的透镜调查中进行改进。
ContextStudying the statistical properties of the large-scale structure in the Universe with weak gravitational lensing is a prime goal of several current and forthcoming galaxy surveys. The power that weak lensing has to constrain cosmological parameters can be enhanced by considering statistics beyond second-order shear correlation functions or power spectra. One such higher-order probe that has proven successful in observational data is density split statistics (DSS), in which one analyses the mean shear profiles around points that are classified according to their foreground galaxy density.AimsIn this paper, we generalise the most accurate DSS model to allow for a broad class of angular filter functions used for the classification of the different local density regions. This approach is motivated by earlier findings showing that an optimised filter can provide tighter constraints on model parameters compared to the standard top-hat case.MethodsAs in the previous DSS model we built on large deviation theory approaches and approximations thereof to model the matter density probability distribution function, and on perturbative calculations of higher-order moments of the density field. The novel addition relies on the generalisation of these previously employed calculations to allow for general filter functions and is validated on several sets of numerical simulations.ResultsIt is shown that the revised model fits the simulation measurements well for many filter choices, with a residual systematic offset that is small compared to the statistical accuracy of current weak lensing surveys. However, by use of a simple calibration method and a Markov chain Monte Carlo analysis, we studied the expected sensitivity of the DSS to cosmological parameters and find unbiased results and constraints comparable to the commonly used two-point cosmic shear measures. Hence, our DSS model can be used in competitive analyses of current cosmic shear data, while it may need refinements for forthcoming lensing surveys.