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arXiv 1506.08486astro-ph.CO
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利用强引力透镜系统进行宇宙学检验

Cosmological test using strong gravitational lensing systems

C. C. Yuan, F. Y. Wang

摘要:

强引力透镜系统作为探索宇宙的重要手段之一,使我们能够比较不同的宇宙学模型,约束重要的宇宙学参数。这一目的可以从强引力透镜系统的动力学和几何学性质,如像的时滞$Δτ$、透镜星系的速度色散$σ$以及这两种效应的组合$Δτ/σ^2$来达到。为了对$Λ$ CDM宇宙和$R_h=ct$宇宙进行一对一的比较,我们使用了一个包含36个强透镜系统的样本,并测量了SLACS和LSD巡天的速度色散。考虑到时间延迟效应,还使用了12个具有$Δτ$的双像透镜系统。此外,使用蒙特卡罗(MC)模拟来比较上述三种方法的效率。通过模拟,我们估计了在$99.7\%$置信水平下排除一个模型所需的晶状体数量。通过与$Δτ$和速度色散$σ$的约束比较,发现使用$Δτ/σ^2$可以提高宇宙学模型之间的区分度。尽管这些方法的独立性检验揭示了$Δτ/σ^2$和$σ$之间的相关性,但如果有更多的数据样本,则可以将$Δτ/σ^2$视为$σ$的改进方法。

英文摘要:

As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay $Δτ$ of images, the velocity dispersion $σ$ of the lensing galaxies and the combination of these two effects, $Δτ/σ^2$. In this paper, in order to carry out one-on-one comparisons between $Λ$CDM universe and $R_h=ct$ universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the SLACS and LSD survey. Concerning the time-delay effect, 12 two-image lensing systems with $Δτ$ are also used. In addition, Monte Carlo (MC) simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the $99.7\%$ confidence level. Comparing with constraints from $Δτ$ and the velocity dispersion $σ$, we find that using $Δτ/σ^2$ can improve the discrimination between cosmological models. Despite the independence tests of these methods reveal a correlation between $Δτ/σ^2$ and $σ$, $Δτ/σ^2$ could be considered as an improved method of $σ$ if more data samples are available.

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。

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