A kinematic classification of the cosmic web
A kinematic classification of the cosmic web
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DOI：
10.1111/j.1365-2966.2012.21553.x
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发表时间：
2012-01
影响因子：
4.8
通讯作者：
Y. Hoffman;Ofer Metuki;G. Yepes;S. Gottlober;J. Forero-Romero;N. Libeskind;A. Knebe
中科院分区：
文献类型：
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作者：
Y. Hoffman;Ofer Metuki;G. Yepes;S. Gottlober;J. Forero-Romero;N. Libeskind;A. Knebe
提出了一种宇宙网分类的新方法。哈恩等人之前工作的延伸。和Forero-Romero等人提出，新算法基于速度剪切张量而不是引力潮汐张量的分析。该过程包括在空间中每个（网格）点构建剪切张量并评估其三个特征向量。根据高于特定阈值（0、1、2 或 3）的特征值数量，将给定点分类为空隙、片材、细丝或结。阈值被视为定义网络的自由参数。该算法已应用于 5 年威尔金森和微波各向异性探针/Λ 冷暗物质 (ΛCDM) 模型框架内边长 64 h−1 Mpc 和 N = 10243 个粒子的盒子的仅暗物质模拟。由此产生的基于速度的宇宙网将结构解析到 ≲0.1 h−1 Mpc 尺度，而不是基于潮汐的宇宙网的 ≈1 h−1 Mpc 尺度。低密度区域由被平面片材平分的延伸空隙组成，其密度也低于平均值。过密区域主要是线性细丝和结。基于速度的宇宙网所实现的分辨率为研究宇宙网框架内晕和星系的形成提供了一个平台。
A new approach for the classification of the cosmic web is presented. In extension of the previous work of Hahn et al. and Forero-Romero et al., the new algorithm is based on the analysis of the velocity shear tensor rather than the gravitational tidal tensor. The procedure consists of the construction of the shear tensor at each (grid) point in space and the evaluation of its three eigenvectors. A given point is classified to be either a void, sheet, filament or a knot according to the number of eigenvalues above a certain threshold, 0, 1, 2 or 3, respectively. The threshold is treated as a free parameter that defines the web. The algorithm has been applied to a dark matter only simulation of a box of side length 64 h−1 Mpc and N = 10243 particles within the framework of the 5-year Wilkinson and Microwave Anisotropy Probe/Λ cold dark matter (ΛCDM) model. The resulting velocity-based cosmic web resolves structures down to ≲0.1 h−1 Mpc scales, as opposed to the ≈1 h−1 Mpc scale of the tidal-based web. The underdense regions are made of extended voids bisected by planar sheets, whose density is also below the mean. The overdense regions are vastly dominated by the linear filaments and knots. The resolution achieved by the velocity-based cosmic web provides a platform for studying the formation of haloes and galaxies within the framework of the cosmic web.