Title: Probing High-redshift Circum/Inter-galactic Medium Using both Emission and Absorption
Speaker: Zheng Cai, Department of Astronomy, Tsinghua University
Host: Jianfeng Wu
Time: 14:30, Thursday, Dec. 24
Location: Physics Building 552
Abstract:
In this talk, I will present our survey of the most massive overdensities (progenitors of Coma cluster) in the peak of cosmic star formation and QSO activities (z=2--4). I will present our discovery of a sample of massive overdensies at z~2.3 by utilizing Subaru/HSC, Keck, CFHT and ALMA, selected using the groups of strong Lya absorption. The galaxy properties in these overdensities reflect the emergence of the environmental dependence of galaxy property. I will further discuss the discovery of enormous Lyman alpha nebulae in these extremely overdense fields at high redshift. These site are unique laboratories to study the preliminary intracluster medium properties and the IGM-galaxy interactions. Moreover, I will present our new observations of Lyman alpha nebulae using Keck Cosmic Web Imager (KCWI). In the end, I will talk about the future prospects of how greatly improve our understanding of the structure formation in the next decade with LSST, CMB-S4 and a potentially new opportunity of a planned 6.5m spectroscopic telescope.
Bio:
蔡峥，清华大学天文系副教授，2008年毕业于中国科学技术大学，2015年获得美国亚利桑那大学天体物理学博士学位，2015年—2019年在美国加州大学圣克鲁兹分校从事博士后研究，2016年获美国太空总署 (NASA) “哈勃学者” (Hubble Fellow) 。他发现宇宙早期大尺度结构以及发现宇宙早期最亮的星云，被美国CNN，英国BBC等主流媒体报道。蔡峥领导（PI）的多项研究入选哈勃太空望远镜、以及地面最大望远镜近千小时的观测计划。他参与新的望远镜研发与科学规划，包括载人航天空间站望远镜（CSST）星系宇宙学无缝光谱子课题负责人，他也正在策划世界最大的光谱巡天望远镜。
