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arXiv 1503.08826astro-ph.COgr-qchep-phhep-th
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关于大尺度结构有效场论中偏置示踪剂的统计

On the Statistics of Biased Tracers in the Effective Field Theory of Large Scale Structures

Raul Angulo, Matteo Fasiello, Leonardo Senatore, Zvonimir Vlah

摘要:

随着普朗克任务的完成,为了继续收集宇宙学信息,了解宇宙的大尺度结构(LSS)的准确性已变得至关重要。LSS的有效场论(EFTofLSS)是一种新的理论框架,旨在发展对LSS在长距离的分析理解,其中不均匀性很小。我们进一步发展的EFTofLSS中的偏置示踪剂的描述,以考虑重子物理和原始非高斯性的影响,发现需要新的偏置系数。然后,我们在高斯初始条件下,对暗物质描述了单圈晕-晕和晕-物质两点函数,以及树能级的晕-晕-晕、物质-晕-晕和物质-物质-晕三点函数的EFTofLSS的预测。在EFTofLSS中需要几个新的偏置系数,即使它们在给定阶次的贡献可以是退化的,并且相同的参数对多个观测量有贡献。我们开发了一种方法,以减少偏见的数量到一个不可约的基础上,并发现,在我们工作的顺序,七个偏见参数足以描述这个非常丰富的统计集。然后,我们比较$N$体模拟的输出。对于最低的质量箱,我们发现百分比水平协议$k\simeq 0.3\,h\,{\rm Mpc}^{-1}$的一个循环两点函数,并高达$k\simeq 0.15\,h\,{\rm Mpc}^{-1}$的树级三点函数,与$k$达到降低与更高的质量箱。这与理论估计是一致的,并表明LSS中的宇宙学信息比以前认为的要多得多。

英文摘要:

With the completion of the Planck mission, in order to continue to gather cosmological information it has become crucial to understand the Large Scale Structures (LSS) of the universe to percent accuracy. The Effective Field Theory of LSS (EFTofLSS) is a novel theoretical framework that aims to develop an analytic understanding of LSS at long distances, where inhomogeneities are small. We further develop the description of biased tracers in the EFTofLSS to account for the effect of baryonic physics and primordial non-Gaussianities, finding that new bias coefficients are required. Then, restricting to dark matter with Gaussian initial conditions, we describe the prediction of the EFTofLSS for the one-loop halo-halo and halo-matter two-point functions, and for the tree-level halo-halo-halo, matter-halo-halo and matter-matter-halo three-point functions. Several new bias coefficients are needed in the EFTofLSS, even though their contribution at a given order can be degenerate and the same parameters contribute to multiple observables. We develop a method to reduce the number of biases to an irreducible basis, and find that, at the order at which we work, seven bias parameters are enough to describe this extremely rich set of statistics. We then compare with the output of $N$-body simulations. For the lowest mass bin, we find percent level agreement up to $k\simeq 0.3\,h\,{\rm Mpc}^{-1}$ for the one-loop two-point functions, and up to $k\simeq 0.15\,h\,{\rm Mpc}^{-1}$ for the tree-level three-point functions, with the $k$-reach decreasing with higher mass bins. This is consistent with the theoretical estimates, and suggests that the cosmological information in LSS amenable to analytical control is much more than previously believed.

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