Future supernovae data and quintessence models
Future supernovae data and quintessence models
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DOI：
10.1046/j.1365-8711.2003.06508.x
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发表时间：
2002-07
影响因子：
4.8
通讯作者：
E. D. Pietro;J. Claeskens
中科院分区：
文献类型：
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作者：
E. D. Pietro;J. Claeskens
研究了用现有和未来的超新星数据确定宇宙暗能量状态方程的可能性。我们认为这个状态方程的四个演化规律对应于四个典型的模型，即（i）宇宙常数，（ii）一般正压流体，（iii）一个完美的流体与线性状态方程和（iv）一个更物理模型的基础上的伪Nambu-Goldstone玻色子场。我们明确地表明，目前不仅在每个模型，而且在不同的模型之间的简并：它们是由暗能量的状态方程和光度距离之间的多积分关系。目前的超新星观测使用标准的方法进行分析，并获得每个模型的最小值进行比较。我们确认，在这些模型之间进行区分，仅使用目前的Ia型超新星数据的困难。通过模拟，我们表明，未来的SNAP观测不会消除所有的简并。例如，如果没有使用正确的宇宙学模型来拟合数据，则可能会发现错误的Ω m估计值为102 m i n。最后，我们给出了一些概率获得明确的结果，免费从退化。特别是，在2σ水平上，将宇宙常数与状态方程不同于-1的真正正压流体混淆的概率为95%。
The possibility of unambiguously determining the equation of state of the cosmic dark energy with existing and future supernovae data is investigated. We consider four evolution laws for this equation of state corresponding to four quintessential models, i.e. (i) a cosmological constant, (ii) a general barotropic fluid, (iii) a perfect fluid with a linear equation of state and (iv) a more physical model based on a pseudo-Nambu-Goldstone boson field. We explicitly show the degeneracies present not only within each model but also between the different models: they are caused by the multi-integral relation between the equation of state of dark energy and the luminosity distance. Present supernova observations are analysed using a standard Χ 2 method and the minimal Χ 2 values obtained for each model are compared. We confirm the difficulty in discriminating between these models using present type Ia supernovae data only. By means of simulations, we then show that future SNAP observations will not remove all the degeneracies. For example, wrong estimations of Ω m with a good value of Χ 2 m i n could be found if the right cosmological model is not used to fit the data. Finally, we give some probabilities for obtaining unambiguous results, free from degeneracies. In particular, the probability of confusing a cosmological constant with a true barotropic fluid with an equation of state different from -1 is shown to be 95 per cent at a 2σ level.