论文标题
使用无尺度模型在$ n $ body模拟中限制成对速度的精度
Constraining accuracy of the pairwise velocities in $N$-body simulations using scale-free models
论文作者
论文摘要
我们提出了一个分析的延续，该分析旨在通过利用大型（最多$ n = 4096^3 $）模拟使用Abacus运行的无尺度宇宙学模拟来量化$ n $ body模拟的分辨率。在这里，我们通过直接估计和通过累积-2PCF（使用对保护方程）来关注物质场的径向成对速度。我们发现，可以在一系列尺度上证明平均相对成对速度的$ 1 \％$水平的收敛性，从早期的几次网格间距演变到后期的尺度略低于此尺度。我们显示了对两个不同盒子大小的分析以及较小框的平均结果，并比较了上述两个估计量在每个尺度上的限制准确性方面的功率。直到平滑参数的顺序范围，收敛是在$ \ sim5 \％$精度下获得的，并显示了指示渐近稳定聚类的行为。我们还推断出LCDM模拟的保守估计值对分辨率的较低临界值的演变（$ 1 \％$和$ 5 \％$ precision）作为RedShift的函数。
We present a continuation of an analysis that aims to quantify resolution of $N$-body simulations by exploiting large (up to $N=4096^3$) simulations of scale-free cosmologies run using Abacus. Here we focus on radial pairwise velocities of the matter field, both by direct estimation and through the cumulative-2PCF (using the pair conservation equation). We find that convergence at the $1\%$ level of the mean relative pairwise velocity can be demonstrated over a range of scales, evolving from a few times the grid spacing at early times to slightly below this scale at late times. We show the analysis of two different box sizes as well as from averaging results from the smaller boxes, and compare the power of the two aforementioned estimators in constraining accuracy at each scale. Down to scales of order of the smoothing parameter, convergence is obtained at $\sim5\%$ precision, and shows a behaviour indicating asymptotic stable clustering. We also infer for LCDM simulations conservative estimates on the evolution of the lower cut-off to resolution (at $1\%$ and $5\%$ precision) as a function of redshift.
