arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0907.4987astro-ph.COhep-ph
收藏

相互作用暗能量模型的观测约束

Observational constraints on an interacting dark energy model

Jussi Valiviita, Roy Maartens, Elisabetta Majerotto

摘要:

我们利用宇宙微波背景各向异性、超新星光度和星系分布中重子声学振荡信号的观测结果,将宇宙学参数约束在一个简单的具有时变状态方程的相互作用暗能量模型中。使用蒙特卡洛马尔可夫链技术,我们确定后验似然。来自单个数据集的约束是弱的,但是三个数据集的组合限制了相互作用常数$Γ$小于宇宙膨胀率的23% $H_0$ ;在95% CL $-0.23 < Γ/H_0 < +0.15$。即使相互作用率大得多,CMB声峰也可以很好地拟合,但这需要比非相互作用模型更大或更小(取决于相互作用的符号)的物质密度。由于物质密度和相互作用速率之间的这种简并性,对CMB的唯一可观察到的影响是更大或更小的积分萨克斯-沃尔夫(ISW)效应。虽然SN或BAO数据本身并不对相互作用设置任何直接约束,但它们排除了具有非常大物质密度的模型,因此当与CMB数据联合分析时,间接约束了相互作用速率。为了实现本文中描述的分析,我们在一篇配套论文[arXiv:0907.4981]中提出了一种新的早期辐射时代解决方案的系统分析,以找到玻尔兹曼积分的绝热初始条件。

英文摘要:

We use observations of cosmic microwave background anisotropies, supernova luminosities and the baryon acoustic oscillation signal in the galaxy distribution to constrain the cosmological parameters in a simple interacting dark energy model with a time-varying equation of state. Using a Monte Carlo Markov Chain technique we determine the posterior likelihoods. Constraints from the individual data sets are weak, but the combination of the three data sets confines the interaction constant $Γ$ to be less than 23% of the expansion rate of the Universe $H_0$; at 95% CL $-0.23 < Γ/H_0 < +0.15$. The CMB acoustic peaks can be well fitted even if the interaction rate is much larger, but this requires a larger or smaller (depending on the sign of interaction) matter density today than in the non-interacting model. Due to this degeneracy between the matter density and the interaction rate, the only observable effect on the CMB is a larger or smaller integrated Sachs-Wolfe (ISW) effect. While SN or BAO data alone do not set any direct constraints on the interaction, they exclude the models with very large matter density, and hence indirectly constrain the interaction rate when jointly analysed with the CMB data. To enable the analysis described in this paper, we present in a companion paper [arXiv:0907.4981] a new systematic analysis of the early radiation era solution to find the adiabatic initial conditions for the Boltzmann integration.

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。

↑