题目：The Brownian motion of FRB bursts in the Time-Energy Bivariate Space

报告人：李菂 研究员 （国家天文台）

地点：紫金港校区西区海纳苑8栋439室

时间：2023.03.03（周五），下午13:30

摘要：

The 'language' used to describe FRBs have been, understandably, largely constrained to those of well-developed and seemingly relevant fields, pulsars and GRBs in particular. In such contexts, though, we cannot even agree on the definition of a single FRB pulse or the existence of sub-pulse. I introduce here some initial efforts of analyzing repeating FRBs based on more general physical systems. The burst series from a repeater can be viewed as a motion path on the arrival time- burst energy bivariate phase space. We utilized Pincus index and Lyapunov index to characterize such motion's stochasticity and chaoticity, respectively. Using the same description, repeating FRBs were found to be more random than solar bursts and earthquakes. Our analyses thus disfavor magnetar-crust-quake model for repeaters. The more significant implication would be the potential of studying FRBs in the context of complex physical systems.  This is among a series of significant developments in the FRB field made possible by FAST. I will also briefly introduce other FAST discoveries and put them in the context of the history of radio astronomy.

个人简介：

李菂，中国科学院国家天文台研究员，FAST（中国天眼）运行与发展中心首席科学家，发表期刊论文300余篇，包括以通讯或第一（含共同）作者发表《Nature》、《Science》正刊论文5篇，《Science Bulletin》封面文章1篇等，授权专利4项。组织领导了FAST早期科学规划和相关研究，提出和主持实现了世界首创的多科学目标同时巡天模式，数倍提高FAST巡天效率。发现星际氧气分子；命名了氢气窄线自吸收方法；提出快速射电暴爆发率双峰结构和重复爆偏振演化统一图景。成果入选2021年度中国科学十大进展，2022年度中国科学十大进展新闻等。参与领导多项大型科学计划和组织，任澳大利亚国家望远镜指导委员会国际委员，突破基金会聆听计划（Breakthrough Listen) 咨询委员等。

欢迎老师和同学参加！