THE HALO MASS FUNCTION FROM EXCURSION SET THEORY. III. NON-GAUSSIAN FLUCTUATIONS
THE HALO MASS FUNCTION FROM EXCURSION SET THEORY. III. NON-GAUSSIAN FLUCTUATIONS
复制标题
偏移集理论中的晕质量函数。
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Riotto
中科院分区：
文献类型：
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作者：
M. Maggiore;A. Riotto
利用偏移集理论计算了原始非高斯性对光晕质量函数的影响。在非高斯性存在的情况下，平滑密度场的随机演化，作为平滑尺度的函数，是非马尔可夫的，除了推广Press-Schechter （PS）理论的“局部”项之外，还有“记忆”项，它们对质量函数的影响可以使用本系列第一篇论文中开发的形式来计算。我们发现，在计算三点相关器对质量函数的影响时，忽略云中云问题并将最终结果乘以蒙混系数（fudge factor）的PS-like方法原则上是不合理的。当在偏移集理论的框架下正确计算时，事实上，“局部”贡献消失了（对于所有奇点相关器，图像高斯的贡献抵消了PS的贡献，而不是加起来），结果完全来自PS理论中不存在的非平凡内存项。然而，事实证明，在大光晕质量的极限下，非高斯性的影响更相关，这些存储项的贡献与PS理论的简单计算相同，加上依赖于三点相关器导数的子主导项。最后，我们将这些结果与本系列第二篇论文中开发的扩散势垒模型结合起来，发现所得质量函数再现了非高斯初始条件下最近的n体模拟，而不引入任何特别参数。
We compute the effect of primordial non-Gaussianity on the halo mass function, using excursion set theory. In the presence of non-Gaussianity, the stochastic evolution of the smoothed density field, as a function of the smoothing scale, is non-Markovian and beside “local” terms that generalize Press–Schechter (PS) theory, there are also “memory” terms, whose effect on the mass function can be computed using the formalism developed in the first paper of this series. We find that, when computing the effect of the three-point correlator on the mass function, a PS-like approach which consists in neglecting the cloud-in-cloud problem and in multiplying the final result by a fudge factor ≃2, is in principle not justified. When computed correctly in the framework of excursion set theory, in fact, the “local” contribution vanishes (for all odd-point correlators the contribution of the image Gaussian cancels the PS contribution rather than adding up), and the result comes entirely from non-trivial memory terms which are absent in PS theory. However it turns out that, in the limit of large halo masses, where the effect of non-Gaussianity is more relevant, these memory terms give a contribution which is the same as that computed naively with PS theory, plus subleading terms depending on derivatives of the three-point correlator. We finally combine these results with the diffusive barrier model developed in the second paper of this series, and we find that the resulting mass function reproduces recent N-body simulations with non-Gaussian initial conditions, without the introduction of any ad hoc parameter.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.