Halo Formation in Warm Dark Matter Models
Halo Formation in Warm Dark Matter Models
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DOI：
10.1086/321541
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发表时间：
2000-10
期刊：
影响因子：
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通讯作者：
P. Bode;J. Ostriker;N. Turok
中科院分区：
文献类型：
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作者：
P. Bode;J. Ostriker;N. Turok
标准冷暗物质(CDM)理论的预测与银河系下尺度上的星团观测之间出现了差异。热暗物质(WDM)是CDM的一种简单修正，其中暗物质粒子具有初始速度，这是由于它们作为热遗迹解耦或通过非平衡衰变形成的。我们用高分辨率的N体码研究了波分复用器的非线性引力聚集，并识别了一些独特的观测信号。与清洁发展机制相比，光晕浓度和核心密度降低，核心半径增加，出现大光晕的低质量卫星要少得多。小光晕的数量被抑制了，而那些存在的光晕是由焦散线“自上而下”碎裂而成的，这是连接巨大光晕的“宇宙网”的一部分。在这张网的外面几乎没有形成小光环。如果我们将小光晕与矮小星系联系起来，那么它们的数量、空间分布和形成纪元似乎与WDM的观测结果比CDM的观测结果更一致。
Discrepancies have emerged between the predictions of standard cold dark matter (CDM) theory and observations of clustering on subgalactic scales. Warm dark matter (WDM) is a simple modification of CDM in which the dark matter particles have initial velocities due either to their having decoupled as thermal relics or to their having been formed via nonequilibrium decay. We investigate the nonlinear gravitational clustering of WDM with a high-resolution N-body code and identify a number of distinctive observational signatures. Relative to CDM, halo concentrations and core densities are lowered, core radii are increased, and large halos emerge with far fewer low-mass satellites. The number of small halos is suppressed, and those present are formed by "top-down" fragmentation of caustics, as part of a "cosmic web" connecting massive halos. Few small halos form outside this web. If we identify small halos with dwarf galaxies, then their number, spatial distribution, and formation epoch appear in better agreement with the observations for WDM than they are for CDM.