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arXiv 1706.07573astro-ph.CO
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用造父变星校准的低红移Ia型超新星$H_0$的盲法测定

A blinded determination of $H_0$ from low-redshift Type Ia supernovae, calibrated by Cepheid variables

Bonnie R. Zhang, Michael J. Childress, Tamara M. Davis, Natallia V. Karpenka, Chris Lidman, Brian P. Schmidt, Mathew Smith

摘要:

目前,哈勃常数$H_0$的值之间存在着一种${>}3σ$张力,该值是由普朗克对宇宙微波背景波动的分析得出的,而局部测量则是使用Ia型超新星(SNe Ia)的校准器进行的。我们对Riess等人2011进行了盲法再分析,以测量来自低红移SNe Ia的$H_0$,通过造父变星和几何距离(包括NGC 4258)进行校准。本文是一个示范的技术应用于Riess等。2016年数据。我们的端到端分析从可用的CfA3和LOSS光度法开始,提供了Riess等人2011的独立验证。我们在整个分析和裁判过程的第一阶段模糊了$H_0$的价值,因为SNe Ia的校准需要一系列通常微妙的选择,并且结果受人为偏见影响的可能性很大。我们的分析与Riess et al. 2011的分析不同,结合了SNLS和JLA中采用的协方差矩阵方法来量化SN Ia系统学,并包括所有SN Ia和造父变星数据的同时拟合。我们发现$H_0 = 72.5 \pm 3.1$(stat)$\pm 0.77$(sys)km s $^{-1}$ Mpc $^{-1}$有一个三星系(NGC 4258+LMC+MW)锚。相对不确定度为4.3%统计学、1.1%系统性和4.4%总不确定度,大于Riess等人2011年(总不确定度为3.3%)和Efstathiou 2014年再分析(总不确定度为3.4%)。我们的错误预算$H_0$主要是由于超新星样本的小尺寸的统计误差,而系统的贡献是占主导地位的造父变星的变化适合,并为超新星Ia,在宿主星系质量的依赖和Malmquist偏差的不确定性。

英文摘要:

Presently a ${>}3σ$ tension exists between values of the Hubble constant $H_0$ derived from analysis of fluctuations in the Cosmic Microwave Background by Planck, and local measurements of the expansion using calibrators of type Ia supernovae (SNe Ia). We perform a blinded reanalysis of Riess et al. 2011 to measure $H_0$ from low-redshift SNe Ia, calibrated by Cepheid variables and geometric distances including to NGC 4258. This paper is a demonstration of techniques to be applied to the Riess et at. 2016 data. Our end-to-end analysis starts from available CfA3 and LOSS photometry, providing an independent validation of Riess et al. 2011. We obscure the value of $H_0$ throughout our analysis and the first stage of the referee process, because calibration of SNe Ia requires a series of often subtle choices, and the potential for results to be affected by human bias is significant. Our analysis departs from that of Riess et al. 2011 by incorporating the covariance matrix method adopted in SNLS and JLA to quantify SN Ia systematics, and by including a simultaneous fit of all SN Ia and Cepheid data. We find $H_0 = 72.5 \pm 3.1$ (stat) $\pm 0.77$ (sys) km s$^{-1}$ Mpc$^{-1}$ with a three-galaxy (NGC 4258+LMC+MW) anchor. The relative uncertainties are 4.3% statistical, 1.1% systematic, and 4.4% total, larger than in Riess et al. 2011 (3.3% total) and the Efstathiou 2014 reanalysis (3.4% total). Our error budget for $H_0$ is dominated by statistical errors due to the small size of the supernova sample, whilst the systematic contribution is dominated by variation in the Cepheid fits, and for the SNe Ia, uncertainties in the host galaxy mass dependence and Malmquist bias.

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