强引力透镜样本在星系及宇宙学研究中的应用

Strong gravitational lensing, one of the consequences of Einstein’s General Theory of Relativity, has developed into an important astrophysical tool for probing cosmology (cosmological parameters) and galaxies (structure and evolution). With the improvements both in observational technology and precision, the number of strong lensing systems detected by various systematic surveys has increased rapidly (KIDS, the large area survey the applicants get involved, has also detected certain number of galactic lensing systems). Based on these large number of lensing systems, several aspects of study will be carried out in this project: (1) Build a relatively complete dataset containing strong gravitational lenses from various surveys like KIDS, and derive essential information of cosmology and galaxy (structure and evolution), combined with different statistical analysis based on lens redshift distribution, etc.; (2) Obtain the measurements of angular diameter distances at the lens reshift, by making comprehensive use of the strong lensing time-delay observations, and furthermore make quantitative study of the cosmic distance-duality relation; (3) Probe the structure of lensing galaxies (especially the mass distribution of inner core region) and the spatial profile of dark matter, by modeling the galactic gravitational lenses with professional softwares; (4) Detect distant faint background galaxies with the lensing magnification, and derive information of high-redshift galaxies by identifying and re-tracing the typical features of lensed images.

作为爱因斯坦广义相对论的预言之一，强引力透镜效应近年来成为宇宙学（宇宙学参数）和星系（星系结构和演化）研究领域的重要工具之一。随着观测技术的改进和观测精度的提高，全球各大巡天探测到的强引力透镜样本数量在不断积累 (本人参与的大天区KIDS巡天也已经搜寻到相当数量的星系强引力透镜样本)。 针对这些强引力透镜样本，我们将开展以下几个方面研究：(1) 联合KIDS等各大巡天结果建立完备的星系强引力透镜样本库，并利用透镜体的红移分布等统计学方法提取宇宙学、星系结构及演化的信息；(2) 综合利用引力透镜时间延迟效应数据，获取透镜体所处红移的角直径距离的观测，并对宇宙距离对偶关系进行定量分析；(3) 对星系强引力透镜样本进行模型化处理，研究透镜体星系结构（中心核的物质分布）及暗物质的空间分布；(4) 利用强引力透镜体的增亮效应探测遥远昏暗的背景星系，并通过对透镜典型特征的反演提取高红移背景星系的信息。

随着观测技术的不断改进，全球各大巡天探测到的强引力透镜样本数量在不断积累。本项目集中系统研究强引力透镜的理论和探测（收集整理大样本的强引力透镜数据库，并运用不同的统计学方法进行数据分析），提取了宇宙学（暗能量动力学性质等）、星系结构及演化（暗物质分布等）的信息。另一方面，作为一种高红移标准直尺的强力候选体，中光度类星体的致密射电核可以成为角直径距离的重要探针之一。这为利用射电类星体研究精细宇宙学提供了一种重要途径，进而为直接提取宇宙在高红移的演化信息，并对广义相对论进行实验验证打开一扇全新的窗口。最后，本项目还对暗能量的动力学演化开展了系统性研究，并取得了一系列创新性成果。