arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.02465astro-ph.CO
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多示踪剂的Fisher矩阵:所有你可以从大尺度结构中学习,而无需假设模型

Fisher matrix for multiple tracers: all you can learn from large-scale structure without assuming a model

Renan Boschetti, L. Raul Abramo, Luca Amendola

摘要:

星系的功率谱是宇宙学中的核心量之一。它包含了原初暴胀过程、物质成团、重子-光子相互作用、引力效应、星系-物质偏置、宇宙膨胀、奇异速度场等信息。然而,如果不假设一个特定的宇宙学模型,例如$Λ$ CDM和标准重力,这些信息中的大部分是很难提取的。在本文中,我们探索,而不是多少信息可以获得的是独立的宇宙模型,无论是在背景和线性微扰水平。我们确定了一套完整的模型独立的统计,可以通过结合两个红移箱和两个不同的示踪剂。我们特别关注的统计$r(k,z_1,z_2)$,定义为比率的$fσ_8(z)$在两个红移壳,我们展示了如何估计它与Fisher矩阵的方法。最后,我们预测了$r$的约束,可以实现未来的星系调查,并比较它与标准的单示踪剂的结果。我们发现,$r$可以测量的精度从3%到11%,这取决于调查。使用两个示踪剂,我们发现改进的约束高达两个因素。

英文摘要:

The galaxy power spectrum is one of the central quantities in cosmology. It contains information about the primordial inflationary process, the matter clustering, the baryon-photon interaction, the effects of gravity, the galaxy-matter bias, the cosmic expansion, the peculiar velocity field, etc.. Most of this information is however difficult to extract without assuming a specific cosmological model, for instance $Λ$CDM and standard gravity. In this paper we explore instead how much information can be obtained that is independent of the cosmological model, both at background and linear perturbation level. We determine the full set of model-independent statistics that can be constructed by combining two redshift bins and two distinct tracers. We focus in particular on the statistics $r(k,z_1,z_2)$, defined as the ratio of $fσ_8(z)$ at two redshift shells, and we show how to estimate it with a Fisher matrix approach. Finally, we forecast the constraints on $r$ that can be achieved by future galaxy surveys, and compare it with the standard single-tracer result. We find that $r$ can be measured with a precision from 3 to 11%, depending on the survey. Using two tracers, we find improvements in the constraints up to a factor of two.

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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