Topological Evolution of Hydrogen Reionization

主讲人 (Speaker): 

徐怡冬

主讲人单位 (Speaker's Institute): 

国家天文台

邀请人 (Invited by): 

王鑫

时间 (Time): 

星期三, 2019/06/19 - 15:00 to 16:00

地点 (Location): 

珠海校区海滨红楼17栋107 (Rm 107, Red House 17)

摘要 (Abstract): 

       Cosmic dawn and the epoch of reionization (EoR) are among the most important but poorly understood epochs in the history of the universe. The process of hydrogen reionization can be described by the growth of ionized bubbles in the early stage, the percolation stage, and the shrinking of neutral islands during the late stage. While the growth of isolated ionized regions is well described by the “bubble model”, we would need the “island model” for the late epoch of reionization when the topology of the ionization field changes. It is found that the topological evolution of the ionization field can be unambiguously divided into five stages, and the Minkowski Functionals can be used as diagnostic tools to demarcate each evolutionary stage in topology. In particular, the Euler characteristic implicitly indicates the topological transition when one should use the “island model” instead of the “bubble model”. Among the various experiments designed for the cosmic dawn and the EoR signals, I’ll also introduce a lunar orbit low-frequency array that is being planned in China.

主讲人简介 (Speaker's CV): 

徐怡冬博士现在为中国科学院国家天文台副研究员，她2011年从北京大学获得天体物理博士学位后在国家天文台从事博士后研究，并于2014年作为副研究员至今。她主要从事21cm宇宙学、宇宙黎明、宇宙再电离等领域的研究。