arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0906.4430astro-ph.CO
收藏

广义Chaubergin气体的极限

The extreme limit of the generalized Chaplygin gas

Oliver F. Piattella

摘要:

统一的暗物质模型将暗物质和暗能量描述为一个单一的实体,在最简单的情况下,它体现在一个完美的正压流体中。统一暗物质的小绝热扰动具有振荡和衰变的演化特征,这是一个公认的事实,它提供了与观测不一致的宇宙背景辐射各向异性的预测。在本文中,我们研究了广义Chaubergin气体,我们发现,集成Sachs-Wolfe效应排除了$10^{-3} < α< 350$的模型。我们讨论的宇宙背景演化的影响,如果考虑大值的$α$。在这种情况下,宇宙膨胀模仿了一个物质主导的阶段,紧接着是一个德西特阶段,在跃迁红移$z_tr$。多亏了对Ia型超新星构成集的分析,我们才能够放置$z_tr = 0.22$。

英文摘要:

Unified Dark Matter models describe Dark Matter and Dark Energy as a single entity which is, in the simplest case, embodied in a perfect barotropic fluid. It is a well-established fact that small adiabatic perturbations of Unified Dark Matter have an evolution characterised by oscillations and decay which provide predictions on the Cosmic Background Radiation anisotropies which are in poor agreement with observation. In this paper we investigate the generalised Chaplygin gas and we find that the Integrated Sachs-Wolfe effect excludes the model for $10^{-3} < α< 350$. We discuss the implications on the background evolution of the Universe if large values of $α$ are considered. In this case, the Universe expansion mimics a matter-dominated phase abruptly followed by a de Sitter one at the transition redshift $z_tr$. Thanks to an analysis of the type Ia supernovae Constitution set we are able to place $z_tr = 0.22$.

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。

↑