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arXiv 0803.3775astro-ph
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星系团气体质量分数与红移数据对暗能量的约束

Constraints on Dark Energy from Galaxy Cluster Gas Mass Fraction versus Redshift data

Lado Samushia, Bharat Ratra

摘要:

我们使用Allen等人(2008)的星系团气体质量分数与红移数据来约束三种不同的暗能量模型的参数:宇宙学常数主导模型($Λ$ CDM);暗能量的XCDM参数化;以及具有逆幂律势能密度的缓慢滚动标量场模型。(当对多余参数进行积分时,我们使用引入辅助随机变量的替代方法,而不是使用蒙特卡罗马尔可夫链方法。由此产生的约束是一致的,通常比那些来自其他宇宙学数据的约束更大。一个与时间无关的宇宙学常数与星系团的数据非常吻合,但缓慢演化的暗能量还不能排除。

英文摘要:

We use the Allen et al. (2008) galaxy cluster gas mass fraction versus redshift data to constrain parameters of three different dark energy models: a cosmological constant dominated one ($Λ$CDM); the XCDM parameterization of dark energy; and a slowly-rolling scalar field model with inverse-power-law potential energy density. (Instead of using the Monte Carlo Markov Chain method, when integrating over nuisance parameters we use an alternative method of introducing an auxiliary random variable.) The resulting constraints are consistent with, and typically more constraining than, those derived from other cosmological data. A time-independent cosmological constant is a good fit to the galaxy cluster data, but slowly evolving dark energy cannot yet be ruled out.

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