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arXiv 0812.3149astro-ph
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宇宙学N体模拟中基于网格的线性中微子微扰

Grid Based Linear Neutrino Perturbations in Cosmological N-body Simulations

Jacob Brandbyge, Steen Hannestad

备注：
17 pages, 15 figures
发表信息：
JCAP 0905:002,2009
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摘要：

我们提出了一种新的，快速和精确的方法，包括在宇宙学N体模拟轻中微子的影响。利用线性中微子微扰理论，在N体模拟中计算引力势时考虑了中微子分量的影响。将该方法与\cite{Brandbyge1}中首次提出的全非线性演化方法进行了比较，发现新方法对\sum m_v \lesssim 0.5 eV在z = 0时的物质功率谱的计算精度优于1%.这个误差的尺度近似为（\sum m_v）^[2]，这使得新的线性中微子方法对于0.05 ~ 0.3 eV范围内的中微子总质量非常精确。在z = 1时，对于\sum m_v \lesssim 0.5 eV，误差低于0.3%，并且在更高的红移下变得可以忽略。这种新方法在计算上比用N体粒子表示中微子分量要有效得多。

英文摘要：

We present a novel, fast and precise method for including the effect of light neutrinos in cosmological N-body simulations. The effect of the neutrino component is included by using the linear theory neutrino perturbations in the calculation of the gravitational potential in the N-body simulation. By comparing this new method with the full non-linear evolution first presented in \cite{Brandbyge1}, where the neutrino component was treated as particles, we find that the new method calculates the matter power spectrum with an accuracy better than 1% for \sum m_ν\lesssim 0.5 eV at z = 0. This error scales approximately as (\sum m_ν)^2, making the new linear neutrino method extremely accurate for a total neutrino mass in the range 0.05 - 0.3 eV. At z = 1 the error is below 0.3% for \sum m_ν\lesssim 0.5 eV and becomes negligible at higher redshifts. This new method is computationally much more efficient than representing the neutrino component by N-body particles.

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