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arXiv 1409.7815astro-ph.COastro-ph.GAastro-ph.HEgr-qc
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AGN哈勃图及其宇宙学意义

The AGN Hubble Diagram and Its Implications for Cosmology

Fulvio Melia

摘要:

利用最近提出的活动星系核(AGN)光度距离测度,检验了在R_h=ct和LCDM宇宙学中宇宙膨胀的预言。这种比较研究与宇宙是否经历了从减速膨胀到加速膨胀的转变这一问题特别相关,根据Ia型SN的研究,这种转变被认为发生在最终将被这些物体采样的红移范围内(0 < z < 1.3)。我们发现,活动星系核哈勃图构建从目前可用的来源不支持存在这样的过渡。虽然活动星系核数据的分散性仍然太大,无法得出任何确定的结论,但这里报告的结果在一定程度上加强了使用其他类型源进行比较分析的类似结果。我们表明,赤池,Kullback和贝叶斯信息准则都一致地产生了~84-96%的可能性,R_h=ct比LCDM更接近“真正的”宇宙学,虽然两个模型都没有充分考虑的数据,这表明一个未知的散射源。

英文摘要:

We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the R_h=ct and LCDM cosmologies. This comparative study is particularly relevant to the question of whether or not the Universe underwent a transition from decelerated to accelerated expansion, which is believed to have occurred---on the basis of Type Ia SN studies---within the redshift range (0 < z < 1.3) that will eventually be sampled by these objects. We find that the AGN Hubble Diagram constructed from currently available sources does not support the existence of such a transition. While the scatter in the AGN data is still too large for any firm conclusions to be drawn, the results reported here nonetheless somewhat strengthen similar results of comparative analyses using other types of source. We show that the Akaike, Kullback, and Bayes Information Criteria all consistently yield a likelihood of ~84-96% that R_h=ct is closer to the "true" cosmology than LCDM is, though neither model adequately accounts for the data, suggesting an unnaccounted-for source of scatter.

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