arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1201.0765astro-ph.CO
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自校准哈勃图

The Self-Calibrating Hubble Diagram

Ulrich Feindt, Marek Kowalski, Kerstin Paech

摘要:

随着越来越多的Ia型超新星(SNe Ia)被观测到,w的统计不确定性已经降低到与系统不确定性相同的程度。在不久的将来,统计误差将进一步减少,因此,如果要取得进一步进展,就需要解决改善系统不确定性的问题。我们研究如何在主要的参考光谱的不确定性-这是一个主要的贡献,系统的不确定性预算-影响的暗能量状态方程参数w从超新星Ia的测量。越来越多的SN观测可以用来减少不确定性,包括参考光谱的扰动作为宇宙学拟合中的滋扰参数,从而“自校准”哈勃图。我们首次将这种方法应用于真实的SNe数据,发现参考光谱的扰动在1%的水平上与零一致。对于未来的调查,我们估计,~3500 SNe将需要我们的方法优于标准方法推导宇宙学参数。

英文摘要:

As an increasing number of well measured type Ia supernovae (SNe Ia) become available, the statistical uncertainty on w has been reduced to the same size as the systematic uncertainty. The statistical error will decrease further in the near future, and hence the improvement of systematic uncertainties needs to be addressed, if further progress is to be made. We study how uncertainties in the primary reference spectrum - which are a main contribution to the systematic uncertainty budget - affect the measurement of the Dark Energy equation of state parameter w from SNe Ia. The increasing number of SN observations can be used to reduce the uncertainties by including perturbations of the reference spectrum as nuisance parameters in a cosmology fit, thus "self-calibrating" the Hubble diagram. We employ this method to real SNe data for the first time and find the perturbations of the reference spectrum consistent with zero at the 1%-level. For future surveys we estimate that ~3500 SNe will be required for our method to outperform the standard method of deriving the cosmological parameters.

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