The velocity shear tensor: tracer of halo alignment
The velocity shear tensor: tracer of halo alignment
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DOI：
10.1093/mnras/sts216
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发表时间：
2012-10
影响因子：
4.8
通讯作者：
N. Libeskind;Y. Hoffman;J. Forero-Romero;S. Gottlober;A. Knebe;M. Steinmetz;A. Klypin
中科院分区：
文献类型：
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作者：
N. Libeskind;Y. Hoffman;J. Forero-Romero;S. Gottlober;A. Knebe;M. Steinmetz;A. Klypin
在宇宙网的背景下，研究了暗物质晕和周围大尺度结构的排列。使用速度剪切张量的本征矢量，相对于LSS研究了亚晕的晕旋、形状和轨道角动量，该本征矢量在非线性区域深处的1 Mpc/h网格上进行评估。结，哀歌，片和空隙与偏见。我们发现，较大的质量晕生活在剪切更各向同性的区域，即膨胀或坍缩更球形。晕的形状和剪切张量的特征向量之间的相关性，与最长（最短）轴的晕形状对齐最慢（最快）崩溃的特征向量。这种相关性是网络独立的，这表明速度剪切是晕排列的基本示踪剂。对于晕自旋与宇宙网的排列也发现了类似的结果。结果表明，高质量晕相对于LSS表现出自旋ip：我们发现，这种自旋ip出现的质量是网络相关的，而不是以前建议的普遍性。虽然弱于晕，subhalo轨道也表现出与LSS对齐，提供了一个可能的洞察银河系卫星系统的高度相关的共同旋转。本研究表明，速度剪切张量构成的自然框架，研究方向性的非线性LSS和晕和星系。
The alignment of dark matter (DM) halos and the surrounding large scale structure (LSS) is examined in the context of the cosmic web. Halo spin, shape and the orbital angular momentum of subhaloes is investigated relative to the LSS using the eigen- vectors of the velocity shear tensor evaluated on a grid with a scale of 1 Mpc/h, deep within the non-linear regime. Knots, laments, sheets and voids are associated with biased. We nd that larger mass haloes live in regions where the shear is more isotropic, namely the expansion or collapse is more spherical. A correlation is found between the halos shape and the eigenvectors of the shear tensor, with the longest (shortest) axis of the halos shape being aligned with the slowest (fastest) collapsing eigenvector. This correlation is web independent, suggest- ing that the velocity shear is a fundamental tracer of the halo alignment. A similar result is found for the alignment of halo spin with the cosmic web. It has been shown that high mass haloes exhibit a spin ip with respect to the LSS: we nd the mass at which this spin ip occurs is web dependent and not universal as suggested previously. Although weaker than haloes, subhalo orbits too exhibit an alignment with the LSS, providing a possible insight into the highly correlated co-rotation of the Milky Ways satellite system. The present study suggests that the velocity shear tensor constitutes the natural framework for studying the directional properties of the non-linear LSS and of halos and galaxies.