Merger trees and the multiplicity function of haloes
Merger trees and the multiplicity function of haloes
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DOI：
10.1093/mnras/282.2.631
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发表时间：
1995-11
影响因子：
4.8
通讯作者：
D. D. C. Rodrigues-D.;P. Thomas
中科院分区：
文献类型：
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作者：
D. D. C. Rodrigues-D.;P. Thomas
本文提出了一种计算等级聚类宇宙学中物质晕合并历史的新方法。线性密度场在一系列尺度上被平滑，然后以密度递减的方式排列，并构造合并树。该方法在许多方面类似于科尔\&凯泽的块模型，但具有许多优点：（i）它保留了关于晕之间的空间相关性的信息，（ii）它使用了一系列重叠的网格，因此在寻找罕见的大质量晕方面要好得多，（iii）它不限于质量比为2的幂的晕，以及（iv）它基于密度场的实际实现，因此可以针对N体模拟进行测试。主要缺点是（i）最小晕质量是晶胞的八倍，相应的动态范围损失，以及（ii）偶尔晕在树中的相对位置不能反映它们的塌陷时间的正确顺序，如从平均晕密度计算的。我们表明，我们的模型表现出所需的缩放行为时，测试幂律谱密度扰动，但它预测更多的大规模晕比平面谱的Press-Schechter形式主义。我们提出了为什么会这样的理由。
We present a new method for calculating the merger history of matter halos in hierarchical clustering cosmologies. The linear density field is smoothed on a range of scales, these are then ordered in decreasing density and a merger tree constructed. The method is similar in many respects to the block model of Cole \& Kaiser but has a number of advantages: (i) it retains information about the spatial correlations between halos, (ii) it uses a series of overlapping grids and is thereby much better at finding rare, high-mass halos, (iii) it is not limited to halos whose mass ratios are powers of two, and (iv) it is based on an actual realization of the density field and so can be tested against N-body simulations. The major disadvantages are (i) the minimum halo mass is eight times the unit cell with a corresponding loss of dynamic range, and (ii) occasionally the relative location of halos in the tree does not reflect the correct ordering of their collapse times, as computed from the mean halo density. We show that our model exhibits the required scaling behaviour when tested on power-law spectra of density perturbations, but that it predicts far more massive halos than does the Press-Schechter formalism for flat spectra. We suggest reasons why this should be so.