论文标题

使用FFTLOG建模临近订单的三分相关函数

Modelling the next-to-leading order matter three-point correlation function using FFTLog

论文作者

Guidi, M., Veropalumbo, A., Branchini, E., Eggemeier, A., Carbone, C.

论文摘要

对大学的大规模结构(LSS)的高阶统计数据,尤其是三分统计的研究为我们提供了有关发光和暗物质之间以及原始高斯性偏差之间偏见关系的独特信息。结果,在改进测量技术和理论建模方面已经付出了很多努力,尤其是在傅立叶空间中。相比之下,在配置空间分析中几乎没有取得进展。这项工作是通过提出一种在配置空间中较高的扰动订单上建模三点统计的新策略来填补这一空白的第一步。从BISPECTRUM的近级订单模型开始,我们使用2D-FFTLOG在配置空间中生成其对应物。我们使用领先的顺序预测来校准该过程,该预测已经存在三点相关函数(3PCF)的分析模型。然后,我们通过将3PCF模型的预测与对无碰撞宇宙N体仿真(DEMNUNI)中问题分布进行的测量进行比较来评估3PCF模型的优点。我们专注于两个红移(z = 0.49和z = 1.05),在当前和未来的Galaxy红移调查范围内。卡方分析表明,在两个红移中,所有三角形配置的临时订单3PCF模型都显着改善,分别增加了红移z = 1.05和z = 0.49的匹配配置的数量。特别是,在最小侧面长度符合非线性状态的三角形构型的重型声学振荡(BAO)尺度上也有显着改善。此处提出的模型的计算成本很高,但并不是大大,代表了迈向星系的完整3pc模型的第一步。

The study of higher-order statistics, particularly three-point statistics, of the Large Scale Structure (LSS) of the Universe provides us with unique information on the biasing relation between luminous and dark matter and on deviations from primordial Gaussianity. As a result, much effort has been put into improving measurement techniques as well as theoretical modelling, especially in Fourier space. Comparatively, little progress has been made, instead, in configuration space analyses. This work represents a first step towards filling this gap by proposing a new strategy for modelling 3-point statistics at higher perturbative orders in configuration space. Starting from the next-to-leading order model for the matter bispectrum, we use 2D- FFTLog to generate its counterpart in configuration space. We calibrate the procedure using the leading order predictions for which an analytic model for the three-point correlation function (3PCF) already exists. Then we assess the goodness of the 3PCF model by comparing its predictions with measurements performed on the matter distribution in collisionless cosmological N-body simulations (DEMNUni). We focus on two redshifts (z = 0.49 and z = 1.05) in the range spanned by current and future galaxy redshift surveys. The chi-square analysis reveals that the next-to-leading order 3PCF models significantly improve over the leading order one for all triangle configurations in both redshifts, increasing the number of matched configurations at redshift z = 1.05 and z = 0.49, respectively. In particular, a significant improvement is also seen on the Baryonic Acoustic Oscillations (BAO) scale for triangle configurations whose smallest side length is well into the nonlinear regime. The computational cost of the model proposed here is high but not prohibitively large and represents the first step towards a complete 3PC model for the galaxies.

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