An adapted filter function for density split statistics in weak lensing
An adapted filter function for density split statistics in weak lensing
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DOI：
10.1051/0004-6361/202038694
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发表时间：
2020-06
影响因子：
6.5
通讯作者：
P. Burger;P. Schneider;V. Demchenko;J. Harnois-Déraps;C. Heymans;H. Hildebrandt;S. Unruh
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文献类型：
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作者：
P. Burger;P. Schneider;V. Demchenko;J. Harnois-Déraps;C. Heymans;H. Hildebrandt;S. Unruh
在弱引力透镜分析中，密度分裂统计量探讨不同(前景)星系数密度区域与其弱透镜信号之间的相关性。目的：本文重新考虑密度分裂统计量，通过构造一个新的角滤波函数来适应星系数密度和切变图样之间的预期关系，从而使加权星系数密度的滤波器与用于量化切变信号的滤波器相匹配。方法利用数值射线跟踪模拟的结果，特别是通过基于半解析模型的星系分布的千禧模拟，为星系密度和切向切变信号构造匹配的自适应滤波函数对。我们比较了新的滤光片和以前使用的TOP-HAT滤光片的性能，并应用于一组不同和独立的数值模拟(SLICS，COSMO-SLICS)。结果表明，改进的滤光片在总物质和星系分布之间产生了更好的相关性。此外，改进的滤光片提供了更大的信噪比来限制总物质和星系分布之间的偏差，我们表明，总的来说，它是不同宇宙学之间更灵敏的鉴别器，除了σ8值非常大的宇宙学。所有的分析都得出了这样的结论：在未来的密度分裂统计工作中，我们的自适应滤波器应该是被看好的。
Context.The density split statistics in weak gravitational lensing analyses probes the correlation between regions of different (foreground) galaxy number densities and their weak lensing signal, which is measured by the shape distortion of background galaxies.Aims.In this paper, we reconsider density split statistics, by constructing a new angular filter function that is adapted to the expected relation between the galaxy number density and shear pattern, in a way that the filter weighting the galaxy number density is matched to the filter that is used to quantify the shear signal.Methods.We used the results of numerical ray-tracing simulations, specifically through the Millennium Simulation supplemented by a galaxy distribution based on a semi-analytic model, to construct a matched pair of adapted filter functions for the galaxy density and the tangential shear signal. We compared the performance of our new filter to the previously used top-hat filter, applying both to a different and independent set of numerical simulations (SLICS, cosmo-SLICS).Results.We show that the adapted filter yields a better correlation between the total matter and the galaxy distribution. Furthermore, the adapted filter provides a larger signal-to-noise ratio to constrain the bias between the total matter and the galaxy distribution, and we show that it is, in general, a more sensitive discriminator between different cosmologies, with the exception of cosmologies with very largeσ8values. All analyses lead to the conclusion that our adapted filter should be favoured in future density split statistic works.