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arXiv 1908.07213astro-ph.CO
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寻找宇宙学暗区的相互作用

Looking for interactions in the cosmological dark sector

Micol Benetti, Welber Miranda, Humberto A. Borges, Cassio Pigozzo, Saulo Carneiro, Jailson S. Alcaniz

摘要:

我们研究了宇宙流体的暗成分之间的非引力相互作用的观测特征,这可能是由于从膨胀的真空中产生暗粒子或动态暗能量的聚集效应。特别是,我们分析了一类相互作用的模型($Λ$(t)CDM),其特征在于参数$α$,表现在背景水平像冷物质在早期的时候,并倾向于一个宇宙学常数在渐近的未来。在我们的分析中,我们考虑背景和原始扰动的模型的演变。我们使用宇宙微波背景(CMB)的数据与后期的观测,如联合光变曲线分析(JLA)超新星的数据,哈勃空间望远镜(HST)测量的哈勃-勒梅特参数的本地值,和原始氘丰度从Ly $α$系统来测试的观测可行性的模型和它的一些扩展。我们发现,没有偏好的$α$值不同于零(表征相互作用),即使有一些迹象表明正值时,最小的$Λ$(t)CDM模型进行了分析。当宇宙流体的相对论成分中的额外自由度被考虑时,数据支持$α$的负值,这意味着从暗能量到暗物质的能量通量。

英文摘要:

We study observational signatures of non-gravitational interactions between the dark components of the cosmic fluid, which can be either due to creation of dark particles from the expanding vacuum or an effect of the clustering of a dynamical dark energy. In particular, we analyse a class of interacting models ($Λ$(t)CDM), characterised by the parameter $α$, that behaves at background level like cold matter at early times and tends to a cosmological constant in the asymptotic future. In our analysis we consider both background and primordial perturbations evolutions of the model. We use Cosmic Microwave Background (CMB) data together with late time observations, such as the Joint Light-curve Analysis (JLA) supernovae data, the Hubble Space Telescope (HST) measurement of the local value of the Hubble-Lemaître parameter, and primordial deuterium abundance from Ly$α$ systems to test the observational viability of the model and some of its extensions. We found that there is no preference for values of $α$ different from zero (characterising interaction), even if there are some indications for positive values when the minimal $Λ$(t)CDM model is analysed. When extra degrees of freedom in the relativistic component of the cosmic fluid are considered, the data favour negative values of $α$, which means an energy flux from dark energy to dark matter.

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