arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1602.01389astro-ph.COgr-qc
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用Ia型超新星约束宇宙各向同性

Constraining cosmic isotropy with type Ia supernovae

C. A. P. Bengaly,, A. Bernui, J. S. Alcaniz

摘要:

我们通过将宇宙学参数$H_0$和$q_0$约束在天球上来研究宇宙学原理的有效性。我们的分析是在一个低红移制度,以遵循一个模型独立的方法,使用Union2.1和JLA Ia型超新星(SNe)的编译。我们发现,在天空中的$H_0$参数的首选方向是一致的,我们的本地宇宙在Union2.1的情况下,体流运动,而$q_0$方向分析似乎是反相关的$H_0$的两个数据集。此外,我们还测试了这些结果与蒙特卡罗(MC)实现的一致性,发现两个参数的各向异性在$2-3σ$置信水平内均显着,尽管我们发现$H_0$和$q_0$映射与角分布之间存在显着相关性来自JLA汇编的SNe。因此,我们得出结论,检测到的各向异性是本地起源,或引起的非均匀的天体覆盖的SNe数据集。

英文摘要:

We investigate the validity of the Cosmological Principle by constraining the cosmological parameters $H_0$ and $q_0$ through the celestial sphere. Our analyses are performed in a low-redshift regime in order to follow a model independent approach, using both Union2.1 and JLA Type Ia Supernovae (SNe) compilations. We find that the preferred direction of the $H_0$ parameter in the sky is consistent with the bulk flow motion of our local Universe in the Union2.1 case, while the $q_0$ directional analysis seem to be anti-correlated with the $H_0$ for both data sets. Furthermore, we test the consistency of these results with Monte Carlo (MC) realisations, finding that the anisotropy on both parameters are significant within $2-3σ$ confidence level, albeit we find a significant correlation between the $H_0$ and $q_0$ mapping with the angular distribution of SNe from the JLA compilation. Therefore, we conclude that the detected anisotropies are either of local origin, or induced by the non-uniform celestial coverage of the SNe data set.

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