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arXiv 1403.0293astro-ph.CO
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首次仅使用超新星星等测量$σ_8$

First measurement of $σ_8$ using supernova magnitudes only

Tiago Castro, Miguel Quartin

摘要:

最近提出了一种方法,它允许转换的弱透镜效应的超新星哈勃图从噪声到信号。这种信号对宇宙中结构的生长敏感,并且特别地可以用作$σ_8$的测量,其独立于更传统的方法,例如基于CMB、宇宙剪切或簇丰度的那些方法。我们在这里扩展分析,使内在的非高斯性的超新星PDF,并讨论如何使用贝叶斯因子最好的建模。虽然精确测量$σ_8$需要~ $10^5$超新星,但目前的数据已经允许重要的原理证明。特别是,我们利用最近的JLA目录中的z < 1的732颗超新星,并表明用一对讨厌的参数对固有非高斯性进行简单处理就足以使我们的方法在$2σ$置信水平下产生值$σ_8 = 0.84^{+0.28}_{-0.65}$或$σ_8 < 1.45$。这一结果与模拟结果一致,也与独立测量结果一致,并首次单独使用超新星星等对$σ_8$进行测量。

英文摘要:

A method was recently proposed which allows the conversion of the weak-lensing effects in the supernova Hubble diagram from noise into signal. Such signal is sensitive to the growth of structure in the universe, and in particular can be used as a measurement of $σ_8$ which is independent from more traditional methods such as those based on the CMB, cosmic shear or cluster abundance. We extend here that analysis to allow for intrinsic non-Gaussianities in the supernova PDF, and discuss how this can be best modelled using the Bayes Factor. Although it was shown that a precise measurement of $σ_8$ requires ~$10^5$ supernovae, current data already allows an important proof of principle. In particular we make use of the 732 supernovae with z < 1 of the recent JLA catalog and show that a simple treatment of intrinsic non-Gaussianities with a couple of nuisance parameters is enough for our method to yield the values $σ_8 = 0.84^{+0.28}_{-0.65}$ or $σ_8 < 1.45$ at a $2σ$ confidence level. This result is consistent with mock simulations and it is also in agreement with independent measurements and presents the first ever measurement of $σ_8$ using supernova magnitudes alone.

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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