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arXiv 1303.0337astro-ph.CO
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相关随机游动的游程集理论

Excursion Set Theory for Correlated Random Walks

Arya Farahi, Andrew J. Benson

摘要:

在相关随机游动的情形下,给出了一种新的计算首过分布的方法。结合Maggiore & Riotto的路径积分形式和Zhang & Hui,Benson等人的积分方程解,我们找到了一个数值上稳健且方便的算法,来导出不相关随机游动极限附近的微扰展开式的首过分布。我们应用这种方法的高斯随机密度场过滤高斯平滑函数的特定情况下。通过比较我们的解决方案的第一个交叉分布的Monte Carlo计算的结果,我们表明,我们的方法准确的功率谱$P(k)\propto k^n$的$n=1$,变得不太准确的$n$较小的值。因此,它是对Musso & Sheth方法的补充,Musso & Sheth方法因此将对标准$Λ$ CDM功率谱更有用。我们的方法是相当普遍的,可以适应其他平滑函数,也非高斯密度场。

英文摘要:

We present a new method to compute the first crossing distribution in excursion set theory for the case of correlated random walks. We use a combination of the path integral formalism of Maggiore & Riotto, and the integral equation solution of Zhang & Hui, and Benson et al. to find a numerically robust and convenient algorithm to derive the first crossing distribution in terms of a perturbative expansion around the limit of an uncorrelated random walk. We apply this methodology to the specific case of a Gaussian random density field filtered with a Gaussian smoothing function. By comparing our solutions to results from Monte Carlo calculations of the first crossing distribution we demonstrate that our method accurate for power spectra $P(k)\propto k^n$ for $n=1$, becoming less accurate for smaller values of $n$. It is therefore complementary to the method of Musso & Sheth, which will therefore be more useful for standard $Λ$CDM power spectra. Our approach is quite general, and can be adapted to other smoothing functions, and also to non-Gaussian density fields.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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