论文标题
最终SDSS-IV版本中使用Baryon声学振荡的模型选择
Model Selection using Baryon Acoustic Oscillations in the Final SDSS-IV Release
论文作者
论文摘要
在宇宙物质分布中，红移至〜3.5的宇宙物质分布中看到的重子振荡（BAO）峰反映了首先在宇宙微波背景的温度各向异性中鉴定出的声音地平线的持续膨胀。现在，使用星系可以测量BAO峰位置比〜1％的精度，而使用Ly-Alpha Forrest和类星体的聚类，精度约为1％。结合Alcock-Paczyński（AP）效应，这是由于角度与空间/红移尺寸的变化（假定的）球形对称源分布与距离的距离，BAO测量值被视为评估Univerry的几何形状的最强大工具之一。在本文中，我们采用了五个BAO峰值测量，从斯隆数字天空调查IV的最终发布中，平均红移<z> = 0.38、0.51、0.70、0.70、1.48和2.33，以直接直接对标准模型进行直接面对面的比较，lambda-cdm，lambda-cdm，lambda-cdm，其主要竞争者，以及它的一个已知竞争者，已知的是ct r _ = ct ct cot ct con = ct。为了完整性，我们将AP诊断的补充量较平均的距离探测器，该探针假定恒定距离距离R_D。这两个探针都没有不确定的参数，例如哈勃常数，因此非常适合这种模型选择。我们发现，这些测量值与仅基于AP效应的标准模型相比，R_H = CT受到偏爱，可能性〜75％比〜25％，而Planck-Lambda-CDM比R_H = CT相比，仅基于体积平均距离探针，而距离距离距离距离距离为〜80％，而〜80％对〜20％。使用这两种探针的联合分析都会产生不确定的结果，从而产生与这两种模型的可比性。因此，我们无法通过这项工作确认BAO数据本身支持加速宇宙。
The baryon acoustic oscillation (BAO) peak, seen in the cosmic matter distribution at redshifts up to ~3.5, reflects the continued expansion of the sonic horizon first identified in temperature anisotropies of the cosmic microwave background. The BAO peak position can now be measured to better than ~1% accuracy using galaxies, and ~1.4-1.6% precision with Ly-alpha forrests and the clustering of quasars. In conjunction with the Alcock-Paczyński (AP) effect, which arises from the changing ratio of angular to spatial/redshift size of (presumed) spherically-symmetric source distributions with distance, the BAO measurement is viewed as one of the most powerful tools to use in assessing the geometry of the Universe. In this paper, we employ five BAO peak measurements from the final release of the Sloan Digital Sky Survey IV, at average redshifts <z>=0.38, 0.51, 0.70, 1.48 and 2.33, to carry out a direct head-to-head comparison of the standard model, Lambda-CDM, and one of its principal competitors, known as the R_h=ct universe. For completeness, we complement the AP diagnostic with a volume-averaged distance probe that assumes a constant comoving distance scale r_d. Both probes are free of uncertain parameters, such as the Hubble constant, and are therefore ideally suited for this kind of model selection. We find that R_h=ct is favored by these measurements over the standard model based solely on the AP effect, with a likelihood ~75% versus ~25%, while Planck-Lambda-CDM is favored over R_h=ct based solely on the volume-averaged distance probe, with a likelihood ~80% versus ~20%. A joint analysis using both probes produces an inconclusive outcome, yielding comparable likelihoods to both models. We are therefore not able to confirm with this work that the BAO data, on their own, support an accelerating Universe.
