期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 383, 期 2, 页码 615-626出版社
BLACKWELL PUBLISHING
DOI: 10.1111/j.1365-2966.2007.12570.x
关键词
gravitation; galaxies : formation; galaxies : haloes; cosmology : theory; dark matter
We present a simple and efficient empirical algorithm for constructing dark matter halo merger trees that reproduce the distribution of trees in the Millennium cosmological N-body simulation. The generated trees are significantly better than EPS trees. The algorithm is Markovian, and it therefore fails to reproduce the non-Markov features of trees across short time-steps, except for an accurate fit to the evolution of the average main progenitor. However, it properly recovers the full main-progenitor distribution and the joint distributions of all the progenitors over long-enough time-steps, Delta omega similar or equal to Delta z > 0.5, where omega similar or equal to 1.69/D(t) is the self-similar time variable and D(t) refers to the linear growth of density fluctuations. We find that the main-progenitor distribution is lognormal in the variable sigma(2)(M), the variance of linear density fluctuations in a sphere encompassing mass M. The secondary progenitors are successfully drawn one by one from the remaining mass using a similar distribution function. These empirical findings may be clues to the underlying physics of merger-tree statistics. As a byproduct, we provide useful, accurate analytic time-invariant approximations for the main-progenitor accretion history and for halo merger rates.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据