Which cosmological model—with dark energy or modified FRW dynamics?
Which cosmological model—with dark energy or modified FRW dynamics?
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DOI：
10.1016/j.physletb.2005.12.049
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发表时间：
2005-09
影响因子：
4.4
通讯作者：
M. Szydłowski;W. Godłowski
中科院分区：
文献类型：
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作者：
M. Szydłowski;W. Godłowski
最近对遥远的Ia型超新星（SNIa）的测量以及其他观测表明，我们的宇宙正处于加速膨胀阶段。原则上，对于这样的加速有两种解释（也有可能是宇宙学模型中的不均匀性驱动的加速）。第一种方法假设一个未知形式的能量违反了强能量条件，而第二个假设一些修改的FRW动力学。这两种方法都与当今的观测结果吻合得很好，这导致了模型选择的困难。我们使用赤池（AIC）和贝叶斯（BIC）的模型选择的信息标准，以克服这种退化，并确定一组参数的模型，它给出了最佳的拟合SNIa数据。我们认为五个代表性的进化情景中的每一组。在暗能量的提议中有ΛCDM模型、带幻影场的CDM模型、带拓扑缺陷的CDM模型、带Chaubergin气体的模型和带线性动力学状态方程参数的模型。作为替代的原型方案，我们考虑：膜世界Dvali-Gabadadze-Porrati的情况下，膜模型在兰德尔Sundrum的情况下，卡达西模型与尘埃物质和辐射，弹跳模型与宇宙常数和度量仿射引力（MAG）启发的宇宙学模型。应用模型选择标准，我们表明，AIC和BIC表明，额外的贡献所产生的非标准FRW动态是没有必要解释SNIa。采用模型选择信息准则，我们证明了AIC表示平坦幻影模型，而BIC表示平坦幻影和平坦ΛCDM模型。
Recent measurements of distant type Ia supernovae (SNIa), as well as other observations, indicate that our universe is in an accelerating phase of expansion. In principle, there are two alternative explanations for such an acceleration (there is also a possibility that the acceleration can be driven by inhomogenities in cosmological models). The first approach postulates an unknown form of energy violating the strong energy condition, while the second postulates some modification of FRW dynamics. Both approaches agree well with present-day observations which results in the difficulty of choosing the model. We use the Akaike (AIC) and Bayesian (BIC) information criteria of model selection to overcome this degeneracy and to determine a model with a set of parameters which gives the most preferred fit to the SNIa data. We consider five representative evolutionary scenarios in each of the groups. Among the dark energy proposals are the ΛCDM model, the CDM model with phantom field, CDM model with topological defect, a model with the Chaplygin gas, and a model with a linear dynamical equation of state parameter. As alternative prototype scenarios we consider: the brane world Dvali–Gabadadze–Porrati scenario, brane models in Randall–Sundrum scenario, Cardassian models with dust matter and radiation, a bouncing model with the cosmological constant and metric-affine gravity (MAG) inspired cosmological models. Applying the model selection criteria, we show that both AIC and BIC indicate that additional contributions arising from non-standard FRW dynamics are not necessary to explain SNIa. Adopting the model selection information criteria, we show that the AIC indicates the flat phantom model while BIC indicates both flat phantom and flat ΛCDM models.