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首页> 外文期刊>The Astrophysical journal >PERTURBATIVE ANALYSIS OF ADAPTIVE SMOOTHING METHODS IN QUANTIFYING LARGE-SCALE STRUCTURE
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PERTURBATIVE ANALYSIS OF ADAPTIVE SMOOTHING METHODS IN QUANTIFYING LARGE-SCALE STRUCTURE

机译：量化大型结构的自适应平滑方法的微扰分析

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摘要

Smoothing operation to make a continuous density field from the observed pointlike distribution of galaxies is crucially important for topological or morphological analysis of the large-scale structure, such as the genus statistics or the area statistics (or, equivalently, the level-crossing statistics). It has been pointed out that the adaptive smoothing filters are more efficient tools to resolve cosmic structures than the traditional spatially fixed filters. We study weakly nonlinear effects caused by two representative adaptive methods often used in smoothed hydrodynamical particle (SPH) simulations. Using the framework of second-order perturbation theory, we calculate the generalized skewness parameters for the adaptive methods in the case of fluctuations that are initially power-law fluctuations. Then we apply the multidimensional Edgeworth expansion method and investigate the weakly nonlinear evolution of the genus statistics and the area statistics. Isodensity contour surfaces are often parameterized by the volume fraction of the regions above a given density threshold. We also discuss this parameterization method in perturbative manner.
机译：平滑操作以从观测到的星点状分布中产生连续的密度场对于大规模结构的拓扑或形态分析（例如属统计或面积统计（或等效地，平交统计））至关重要。 。已经指出，与传统的空间固定滤波器相比，自适应平滑滤波器是解决宇宙结构的更有效工具。我们研究由平滑流体力学粒子（SPH）模拟中经常使用的两种代表性自适应方法引起的弱非线性效应。使用二阶摄动理论的框架，我们计算了最初为幂律波动的波动情况下自适应方法的广义偏度参数。然后，我们应用多维Edgeworth展开方法，研究属统计和面积统计的弱非线性演化。等密度轮廓表面通常通过高于给定密度阈值的区域的体积分数进行参数化。我们还将以微扰的方式讨论此参数化方法。

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