Curvature from Strong Gravitational Lensing: A Spatially Closed Universe or Systematics?
Curvature from Strong Gravitational Lensing: A Spatially Closed Universe or Systematics?
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DOI：
10.3847/1538-4357/aaa76f
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
Zhengxiang Li;Xuheng Ding;Guo-Jian Wang;Kai Liao;Zong-hong Zhu
中科院分区：
文献类型：
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作者：
Zhengxiang Li;Xuheng Ding;Guo-Jian Wang;Kai Liao;Zong-hong Zhu
对空间曲率的模型无关约束不仅与宇宙演化和暗能量性质等重要问题密切相关，而且还提供了对哥白尼基本原理有效性的检验。本文利用Friedmann-Lemaintre-Robertson-步行者度规中的距离和规则，利用最新的Ia型超新星和强引力透镜观测数据，实现了与模型无关的空间曲率测量.我们发现，一个空间封闭的宇宙是首选。此外，通过考虑不同类型的速度分散和子样本，我们研究了可能影响SGL观测的空间曲率的模型无关估计的可能因素。我们认为，不同巡天观测数据的组合可能会导致系统偏差，而当只使用来自斯隆透镜巡天的子样本或考虑对透镜密度剖面进行更复杂的处理时，空间平坦宇宙和SGL观测之间的紧张关系会得到缓解。
Model-independent constraints on the spatial curvature are not only closely related to important problems, such as the evolution of the universe and properties of dark energy, but also provide a test of the validity of the fundamental Copernican principle. In this paper, with the distance sum rule in the Friedmann–Lemaître–Robertson–Walker metric, we achieve model-independent measurements of the spatial curvature from the latest type Ia supernovae and strong gravitational lensing (SGL) observations. We find that a spatially closed universe is preferred. Moreover, by considering different kinds of velocity dispersion and subsamples, we study possible factors that might affect model-independent estimations for the spatial curvature from SGL observations. It is suggested that the combination of observational data from different surveys might cause a systematic bias, and the tension between the spatially flat universe and SGL observations is alleviated when the subsample only from the Sloan Lens ACS Survey is used or a more complex treatment for the density profile of lenses is considered.