论文标题
用Alcock-Paczynski效应评估宇宙加速
Assessing Cosmic Acceleration with the Alcock-Paczynski Effect in the SDSS-IV Quasar Catalog
论文作者
论文摘要
可以使用Alcock-Paczynski（AP）效应探测宇宙的几何形状，其中观察到的源相对于其角度大小的球形分布的红移大小根据假定的宇宙学模型而变化。然而，过去的这种效果的应用受到了限制，但是由于缺乏合适的来源和缓解天体物理因素，例如内部红移空间扭曲和众所周知的源演变。在这封信中，我们基于AP效应引入了一项新的测试，该测试避免了使用空间绑定的系统，而是依靠Sloan Digital Sky Survey IV中的红移z <1.5的类星体样本IV，可能会扩展到更高的红移并在即将到来的Surves扩展时提高精度。我们在这里使用这种方法来探测三个相关的Friedmann-Lemaitre-Robertson-Walker（FLRW）宇宙学：LCDM的红移依赖性扩张率，该速度可以预测从减速到Z〜0.7的加速度的过渡；爱因斯坦·德·保姆，其中宇宙总是在减速； R_H = CT Universe，以恒定速率扩展。 LCDM与这些数据一致，但是R_H = CT总体上受到青睐。
The geometry of the Universe may be probed using the Alcock-Paczynski (AP) effect, in which the observed redshift size of a spherical distribution of sources relative to its angular size varies according to the assumed cosmological model. Past applications of this effect have been limited, however, by a paucity of suitable sources and mitigating astrophysical factors, such as internal redshift-space distortions and poorly known source evolution. In this Letter, we introduce a new test based on the AP effect that avoids the use of spatially bound systems, relying instead on sub-samples of quasars at redshifts z < 1.5 in the Sloan Digital Sky Survey IV, with a possible extension to higher redshifts and improved precision when this catalog is expanded by upcoming surveys. We here use this method to probe the redshift-dependent expansion rate in three pertinent Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies: LCDM, which predicts a transition from deceleration to acceleration at z ~ 0.7; Einstein-de Sitter, in which the Universe is always decelerating; and the R_h=ct universe, which expands at a constant rate. LCDM is consistent with these data, but R_h=ct is favoured overall.
