arXiv 1802.092162018-02astro-ph.CO

结合$Λ$ CDM背景的精华：消除$σ_8$张力

Coupled quintessence with a $Λ$CDM background: removing the $σ_8$ tension

Bruno J. Barros, Luca Amendola, Tiago Barreiro, Nelson J. Nunes

备注：: 8 pages, 6 figures. V2: Matches published version
发表信息：: JCAP 01 (2019) 007
DOI：: 10.1088/1475-7516/2019/01/007

摘要：

$Λ$ CDM模型的一个众所周知的问题是，在宇宙微波背景实验中发现的相对高水平的聚类（由参数$σ_8$量化）与在宇宙晚期的大规模观测中获得的较小聚类之间存在张力。在本文中，我们表明，耦合的精髓，即一个单一的暗能量标量场共形耦合到暗物质通过一个常数耦合，可以解决这个问题，如果采取的背景是相同的$Λ$ CDM之一。我们发现，两个竞争的影响出现。一方面，额外的标量力是有吸引力的，因此预计会增加集群。另一方面，为了获得与$Λ$ CDM相同的背景，耦合精粹在当前历元附近必须具有更少量的暗物质。我们表明，第二种效应在当今占据主导地位，并导致整体增长放缓。通过与红移畸变数据的比较，我们发现，在$Λ$ CDM背景下的耦合精华解决了早期成团和晚期成团之间的紧张关系。我们发现对于耦合$β$和对于$σ_8$，最佳拟合值为$|β| = 0.079^{+ 0.059}_{- 0.067}$和$σ_8 = 0.818^{+0.115}_{-0.088}$。这些值也符合KiDS-450调查的透镜数据。我们还估计，未来的任务SKA和Euclid将约束$β$的误差为$\pm\, 1.5\times10^{-3}$和$σ_8$的$\pm \,1.8\times10^{-3}$在$1σ$水平。

英文摘要：

A well-known problem of the $Λ$CDM model is the tension between the relatively high level of clustering, as quantified by the parameter $σ_8$, found in cosmic microwave background experiments and the smaller one obtained from large-scale observations in the late Universe. In this paper we show that coupled quintessence, i.e. a single dark energy scalar field conformally coupled to dark matter through a constant coupling, can solve this problem if the background is taken to be identical to the $Λ$CDM one. We show that two competing effects arise. On one hand, the additional scalar force is attractive, and is therefore expected to increase the clustering. On the other, in order to obtain the same background as $Λ$CDM, coupled quintessence must have a smaller amount of dark matter near the present epoch. We show that the second effect is dominating today and leads to an overall slower growth. Comparing to redshift distortion data, we find that coupled quintessence with $Λ$CDM background solves the tension between early and late clustering. We find for the coupling $β$ and for $σ_8$ the best fit values $|β| = 0.079^{+ 0.059}_{- 0.067}$ and $σ_8 = 0.818^{+0.115}_{-0.088}$. These values also fit the lensing data from the KiDS-450 survey. We also estimate that the future missions SKA and Euclid will constrain $β$ with an error of $\pm\, 1.5\times10^{-3}$ and for $σ_8$ of $\pm \,1.8\times10^{-3}$ at $1σ$ level.

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。

摘要：

英文摘要：

相关论文