Cosmological constraints on extended Galileon models
Cosmological constraints on extended Galileon models
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DOI：
10.1088/1475-7516/2012/03/025
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发表时间：
2012
影响因子：
6.4
通讯作者：
A. D. Felice;S. Tsujikawa
中科院分区：
文献类型：
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作者：
A. D. Felice;S. Tsujikawa
扩展伽利略模型拥有带有德西特吸引子的跟踪器解，在物质主导时期，暗能量状态方程是恒定的，即 wDE = −1−s，其中 s 是正常数。即使有了这个幻影状态方程，也存在可行的参数空间，其中不存在幻影和拉普拉斯不稳定性。利用Ia型超新星、宇宙微波背景（CMB）和重子声振荡的观测数据，我们对背景水平的跟踪器解进行约束，发现在平坦宇宙中参数s被约束为s=0.034−0.034+0.327（95%CL）。为了打破模型之间的简并性，我们还研究了与大尺度结构（LSS）和宇宙微波背景中的积分萨克斯沃尔夫（ISW）效应相关的宇宙密度扰动的演化。我们表明，根据模型参数，LSS 和 ISW 效应呈正相关或负相关。然后可以进一步根据 ISW-LSS 互相关的观测数据以及物质功率谱来约束可行的参数空间。
The extended Galileon models possess tracker solutions with de Sitter attractors along which the dark energy equation of state is constant during the matter-dominated epoch, i.e. wDE = −1−s, where s is a positive constant. Even with this phantom equation of state there are viable parameter spaces in which the ghosts and Laplacian instabilities are absent. Using the observational data of the supernovae type Ia, the cosmic microwave background (CMB), and baryon acoustic oscillations, we place constraints on the tracker solutions at the background level and find that the parameter s is constrained to be s = 0.034−0.034+0.327 (95 % CL) in the flat Universe. In order to break the degeneracy between the models we also study the evolution of cosmological density perturbations relevant to the large-scale structure (LSS) and the Integrated-Sachs-Wolfe (ISW) effect in CMB. We show that, depending on the model parameters, the LSS and the ISW effect is either positively or negatively correlated. It is then possible to constrain viable parameter spaces further from the observational data of the ISW-LSS cross-correlation as well as from the matter power spectrum.