可变的广义Chaplygin气体的演化及其结构形成

在Friedmann理论框架下,将可变的广义Chaplygin气体（VGCG）作为一种暗能量模型,研究了与其相关的宇宙学量的演化规律.在此基础上,通过导出相关的物理量（诸如：物质的密度反差,增长变量和增长因子）所满足的运动方程,并对其求数值解,我们不仅给出了它们的演化图,深入探讨了相应的演化规律,而且还与ΛCDM模型做比较,讨论了此暗能量模型对宇宙结构形成的影响.研究结果表明,当今宇宙是从过去的减速膨胀演化为现在乃至将来的加速膨胀,并且在近阶段可以模拟ΛCDM模型的演化,它与目前的天文观测符合得较好.

The evolution of the variable generalized Chaplygin gas and the structure formation

In the framework of the Friedmann theory the variable generalized Chaplygin gas （VGCG） and the evolutions of the related cosmological quantities are investigated in this paper. On the basis of it, by deriving and solving the differential equations satisfied by the related physical quantities （such as the matter density contrast, growth variable and growth index）, we not only give their evolution trajectories and deeply explore the corresponding evolutionary laws, but also compare with the ACDM model and discuss the effects of the VGCG model on the structure formation. The results show that in the VGCG model the evolution of our universe is from deceleration in the past to acceleration now and in the future, and it can be mimic to that of ACDM model at the recent period, which is better fit to the current astronomical observations.