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arXiv 0902.2814astro-ph.CO
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辐射时代对暗物质3-Pt函数的贡献

Contributions to the Dark Matter 3-Pt Function from the Radiation Era

A. Liam Fitzpatrick, Leonardo Senatore, Matias Zaldarriaga

摘要:

我们考虑了模式重新进入视界后非线性增长对物质密度涨落三点函数的贡献,并讨论了为了预测三点函数而必须包括的效应,其精度可与fNL ~ few的原始非高斯性相媲美。特别地,我们注意到在星系巡天中测量到的最短波长模在辐射年代进入视界,因此,辐射年代将它们的三点函数修改了相当于fNL ~ O(4)的星等。在较长的波长上,辐射年代可以忽略,我们发现相对论效应对非线性增长的修正在fNL ~ few水平上变得重要。我们实现了一个简单的方法来数值计算的三点函数,通过求解二阶运动方程的扰动与一阶扰动提供一个源。

英文摘要:

We consider the contribution to the three-point function of matter density fluctuations from nonlinear growth after modes re-enter the horizon, and discuss effects that must be included in order to predict the three-point function with an accuracy comparable to primordial nongaussianities with f_NL ~ few. In particular, we note that the shortest wavelength modes measured in galaxy surveys entered the horizon during the radiation era, and, as a result, the radiation era modifies their three-point function by a magnitude equivalent to f_NL ~ O(4). On longer wavelengths, where the radiation era is negligible, we find that the corrections to the nonlinear growth from relativistic effects become important at the level f_NL ~ few. We implement a simple method for numerically calculating the three-point function, by solving the second-order equations of motion for the perturbations with the first order perturbations providing a source.

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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