中文摘要：

利用高精度大样本A冷暗物质（Acolddarkmatter，ACDM）宇宙学数值模拟的结果，对暗物质主晕与其子晕的自旋方向相关性进行了研究。本文用两者自旋方向夹角的余弦值（COSθ）作为指标，观察（COSθ）随两者之间距离以及红移的变化。若暗物质晕的自旋方向在空间随机分布，则按统计理论可得（COSθ）应为0；若（COSθ）大于0，则表示暗晕之间自旋方向正相关；若（COSθ）小于0，则表示暗晕之间自旋方向反相关。主要得到三个结果：第一，子晕自旋方向在空间的分布非随机，越靠近主晕内部，（COSθ）越大且为正值，与主晕的自旋方向相关性越强烈。当子晕与主晕质量相当时，在主晕的百分之一个维里半径（virialradiusl距离处，耦合信号非常强烈，（COS0）高达约0．8；而在主晕的维里半径距离处，相关性几乎不存在。第二，子晕与主晕的质量比越大，相关性越强烈。当子晕与主晕质量比相同时，对于不同质量主晕，如1011±0.5^M，1012±0.5^h-1^M，1013±0.5^h-1^M,10 14±0.5^h-1M（其中Me为太阳质量，九为无量纲哈勃常数），相关性曲线几乎重合。第三，该相关性不依赖于红移。但高红移处仍需更高精度模拟进一步验证。这是首次对暗物质主晕与其子晕自旋方向相关性进行的系统性研究，且相关强度较类似物理量的相关更强。末尾简要讨论了产生该相关性的可能原因和可深入进行的后续研究。

英文摘要：

We use 13 high resolution ACDM simulations to research spin direction cot- relation between HBT main halo and its subhaloes. We probe how the angle θ between main halo＇s spin and its subhalo＇s spin varies with different distances between them, and draw curves of （cos θ） versus different central distances. If spin directions of subhaloes dis- tributed in space randomly, （cos θ） should be about zero at all distances. We found： First, the smaller the distances, the stronger the correlation. Specially when the mass of sub- halo is comparable to that of its main halo, at one percent of virial radius of main halo, the correlation is very strong, （cosθ） gets as high as 0.8, and at virial radius there＇s al- most no correlation. Second, the correlation depends on bound mass ratio of subhalo and its main halo. When mass ratios are the same, for main haloes of different masses, e.g.s, 1011h-lMe, 1012h-lM, 1013h-lM, 1014h-IM, the correlation curves almost overlap with each other. Third, the correlation doesn＇t depend on red shift, which demands further research by simulations with higher resolution. This is the first systematic research on the spin direction correlation between haloes, and the signal we get is much more higher then the results of other similar research. In the last section, we＇ll discuss possible reasons for the results and numerical effects of simulations.