The subhalo populations of ΛCDM dark haloes
The subhalo populations of ΛCDM dark haloes
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DOI：
10.1111/j.1365-2966.2004.08360.x
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发表时间：
2004-04
影响因子：
4.8
通讯作者：
Liang Gao;S. White;A. Jenkins;F. Stoehr;V. Springel
中科院分区：
文献类型：
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作者：
Liang Gao;S. White;A. Jenkins;F. Stoehr;V. Springel
我们研究了协和CDM宇宙学中暗物质晕的次晕种群。我们使用一个大的宇宙学模拟和各种高分辨率的resimulations的个别集群和星系晕的晕圈人口的系统学研究的范围内的1000晕质量和1000的母晕圈质量的比率。不同晕的次晕种群不是彼此的比例拷贝，而是随着晕的性质而系统地变化。平均而言，子结构的数量随着晕质量的增加而增加。在固定质量下，它随晕浓度和晕形成红移而减小。这些趋势在规模上与类似晕之间晕下丰度的分散相当。对给定质量的所有晕进行平均，每单位母晕质量的低质量子晕丰度与母晕质量无关。它非常类似于整个宇宙中每单位质量低质量晕的丰度，一旦考虑到亚晕和晕的不同边界定义。在母晕内的次晕的径向分布远不如暗物质集中。它的变化最多与母晕的质量（或浓度）微弱，而不是在所有与subhalo质量。它取决于用于定义所考虑的晕下种群的标准。大约90%的现代次晕是在z = 1之后增生的，大约70%是在z = 0.5之后增生的。在z = 1时吸积的所有晕的总质量中，只有约8%在z = 0时作为束缚子晕存活下来。对于在z = 2处吸积的晕，存活质量分数仅为2%。在母晕中心附近看到的次晕通常比在边缘附近看到的次晕更早吸积，保留的原始质量更少。这些强大的系统性意味着，只有在发光成分的形成被适当地模拟的情况下，才有可能与真实的星系团中的星系进行比较。
We investigate the subhalo populations of dark matter haloes in the concordance �CDM cosmology. We use a large cosmological simulation and a variety of high resolution resimulations of individual cluster and galaxy haloes to study the systematics of subhalo populations over ranges of 1000 in halo mass and 1000 in the ratio of subhalo to parent halo mass. The subhalo populations of different haloes are not scaled copies of each other, but vary systematically with halo properties. On average, the amount of substructure increases with halo mass. At fixed mass, it decreases with halo concentration and with halo formation redshift. These trends are comparable in size to the scatter in subhalo abundance between similar haloes. Averaged over all haloes of given mass, the abundance of low mass subhaloes per unit parent halo mass is independendent of parent mass. It is very similar to the abundance per unit mass of low mass haloes in the universe as a whole, once differing boundary definitions for subhaloes and haloes are accounted for. The radial distribution of subhaloes within their parent haloes is substantially less centrally concentrated than that of the dark matter. It varies at most weakly with the mass (or concentration) of the parent halo and not at all with subhalo mass. It does depend on the criteria used to define the subhalo population considered. About 90 per cent of present-day subhaloes were accreted after z = 1 and about 70 per cent after z = 0.5. Only about 8 per cent of the total mass of all haloes accreted at z = 1 survives as bound subhaloes at z = 0. For haloes accreted at z = 2, the survival mass fraction is just 2 per cent. Subhaloes seen near the centre of their parent typically were accreted earlier and retain less of their original mass than those seen near the edge. These strong systematics mean that comparison with galaxies in real clusters is only possible if the formation of the luminous component is modelled appropriately.