A Lagrangian perturbation theory in the presence of massive neutrinos
A Lagrangian perturbation theory in the presence of massive neutrinos
复制标题
存在大量中微子的拉格朗日微扰理论
DOI：
10.1088/1475-7516/2020/10/034
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发表时间：
2020
影响因子：
6.4
通讯作者：
Arka Banerjee
中科院分区：
文献类型：
--
作者：
A. Aviles;Arka Banerjee
我们发展了一个拉格朗日微扰理论（LPT）框架来研究大质量中微子宇宙学中冷暗物质（CDM）的成团。我们遵循轨道的CDM粒子的拉格朗日位移场的微扰理论的三阶。一旦中微子成为非相对论性的，它们的密度波动被建模为与CDM密度波动成比例，具有尺度依赖的比例因子。这产生了一个引力反作用，它将额外的尺度引入到线性增长函数中，这在高阶LPT内核中得到了解释。通过从欧拉到拉格朗日框架的非线性映射，我们确保我们的理论具有良好的大尺度行为，没有不必要的UV发散，当中微子和CDM密度没有被平等对待时，这是常见的，并且在重申方案中，明显地打破了伽利略不变性。我们使用我们的理论来构建相关函数的基础物质场，以及有偏见的示踪剂使用卷积LPT。使用高斯流模型对红移空间失真效应进行建模。当比较我们的分析结果与\textsc{Quijote}模拟套件中的模拟数据时，我们发现对于没有自由参数的真实的空间和红移空间双粒子关联函数，在红移z=0.5时，在r=20 Mpc h−1时具有良好的精度。同样的精度达到红移空间四极如果我们另外考虑一个有效的场论参数，移动成对的速度色散。为了模拟示踪剂的相关函数，我们采用了一个简单的拉格朗日偏置方案，只使用密度和曲率算子，当与模拟的晕相比时，我们发现它足以达到r=20 Mpc h−1。
We develop a Lagrangian Perturbation Theory (LPT) framework to study the clustering of cold dark matter (CDM) in cosmologies with massive neutrinos. We follow the trajectories of CDM particles with Lagrangian displacements fields up to third order in perturbation theory. Once the neutrinos become non-relativistic, their density fluctuations are modeled as being proportional to the CDM density fluctuations, with a scale-dependent proportionality factor. This yields a gravitational back-reaction that introduces additional scales to the linear growth function, which is accounted for in the higher order LPT kernels. Through non-linear mappings from Eulerian to Lagrangian frames, we ensure that our theory has a well behaved large scale behavior free of unwanted UV divergences, which are common when neutrino and CDM densities are not treated on an equal footing, and in resummation schemes that manifestly break Galilean invariance. We use our theory to construct correlation functions for both the underlying matter field, as well as for biased tracers using Convolution-LPT. Redshift-space distortions effects are modeled using the Gaussian Streaming Model. When comparing our analytical results to simulated data from the \textsc{Quijote} simulation suite, we find good accuracy down to r=20 Mpc h−1 at redshift z=0.5, for the real space and redshift space monopole particle correlation functions with no free parameters. The same accuracy is reached for the redshift space quadrupole if we additionally consider an effective field theory parameter that shifts the pairwise velocity dispersion. For modeling the correlation functions of tracers we adopt a simple Lagrangian biasing scheme with only density and curvature operators, which we find sufficient to reach down to r=20 Mpc h−1 when comparing to simulated halos.
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影响因子：
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