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arXiv 1410.6567astro-ph.CO
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从组合角直径距离得到的宇宙状态方程:光度距离的张力存在吗?

Cosmic equation of state from combined angular diameter distances: Does the tension with luminosity distances exist?

Shuo Cao, Zong-Hong Zhu

摘要:

利用一个相对完整的四个角直径距离(ADD)观测数据和代表当前光度距离(LD)的%合成SN+GRB组合观测数据,研究了在三类暗能量状态方程(EoS)重建情况下,这两种宇宙学距离相容性之间的%张力。特别是,我们使用强引力透镜系统,从各种大型系统的引力透镜调查和星系团,产生哈勃常数的两个角直径距离之间的独立比率$D_{ls}/D_s$数据。我们的研究结果表明,与更一般类别的标准标尺数据,ADD和LD数据是兼容的$1σ$水平。其次,我们注意到,ADD和LD数据%之间的一致性是盲目的,无论EoS参数化:有一个普遍探索的CPL模型和宇宙状态方程的其他配方之间的良好匹配。特别是对于用$β=-2$截断的GEoS模式,用ADD和LD得到的结论几乎一致。最后,统计分析的广义暗能量状态方程上进行的四类ADD数据提供了严格的约束的EoS参数$w_0$,$w_β$和$β$,这表明,暗能量是一个次主导的组成部分在早期。此外,用$β\simeq 1$参数化GEoS似乎是一个更有利的描述宇宙状态方程的双参数模型,因为组合的角直径距离数据(SGL+CBF+BAO+ WMAP 9)提供了最佳拟合值$β=0.751^{+0.465}_{-0.480}$。

英文摘要:

Using a relatively complete observational data concerning four angular diameter distance (ADD) measurements and %synthetic combined SN+GRB observations representing current luminosity distance (LD) data, this paper investigates the %tension between compatibility of these two cosmological distances considering three classes of dark energy equation of state (EoS) reconstruction. In particular, we use strongly gravitationally lensed systems from various large systematic gravitational lens surveys and galaxy clusters, which yield the Hubble constant independent ratio between two angular diameter distances $D_{ls}/D_s$ data. Our results demonstrate that, with more general categories of standard ruler data, ADD and LD data are compatible at $1σ$ level. Secondly, we note that consistency between ADD and LD data %are blind is maintained irrespective of the EoS parameterizations: there is a good match between the universally explored CPL model and other formulations of cosmic equation of state. Especially for the truncated GEoS model with $β=-2$, the conclusions obtained with ADD and LD are almost the same. Finally, statistical analysis of generalized dark energy equation of state performed on four classes of ADD data provides stringent constraints on the EoS parameters $w_0$, $w_β$ and $β$, which suggest that dark energy was a subdominant component at early times. Moreover, the GEoS parametrization with $β\simeq 1$ seems to be a more favorable two-parameter model to characterize the cosmic equation of state, because the combined angular diameter distance data (SGL+CBF+BAO+WMAP9) provide the best-fit value $β=0.751^{+0.465}_{-0.480}$.

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