题目：Find more clusters of galaxies to understand the Universe
报告人：韩金林 研究员(国家杰出青年基金获得者), 中科院国家天文台
时间地点：周四, 2018.9.27下午2:30-4:30, 物理楼552
Clusters of galaxies trace high density region in the cosmic web. We have identified very large samples of galaxy clusters from several survey data. The distribution of galaxy clusters in the Universe is not homogeneous, and we detected the baryon acoustic oscillation from the cluster distribution in space. The huge mass of clusters causes the gravitational lensing effect, and we found many giant arcs in the cluster images which are the lensed features of background galaxies. Based on the distributions of galaxies inside clusters, we can derive dynamical states of galaxy clusters from optical data, which are well-related to cluster mergers and the radio halos. We found that more powerful radio Brightest Cluster Galaxies (BCGs) tend to be these optically very bright galaxies located in more relaxed clusters. The properties of galaxies in clusters depend on environments, e.g. the composite optical luminosity functions are different for galaxies in different locations inside clusters.