报告题目：Measurement of gravitational wave memory
报告人：曹周键 教授（北京师范大学）
报告时间：2021年10月21日（周四）下午15:00-16:00
报告地点：在线报告（腾讯会议ID：657 2489 2600）
报告摘要：
Gravitational wave (GW) memory is an important prediction of general relativity. Existing works on the GW memory detection focus on the waveform analysis. It is hard for waveform analysis method to detect the GW memory due to its quasi-direct current behavior and weakness. We implement a completely different scheme to estimate the GW memory. In this scheme, we firstly apply the Bondi-Metzner-Sachs method to calculate the GW memory of binary black hole based on numerical relativity simulation. Then we construct a surrogate model to relate binary black hole's parameters and the GW memory. Afterwards we apply this surrogate model together with Bayesian techniques to estimate the GW memory of the 48 binary black hole events recorded in O1/O2/O3a. The GW memory corresponding to the all 48 events has been estimated. The most interesting results are for GW190814. The corresponding GW memory is about $-1\times10^{-23}$ and $1\times10^{-23}$ for Hanford detector and Livingston detector respectively. At the meantime we find with 3$\sigma$ C.L. that the memory strain of GW190814 is negative on Hanford detector while positive on Livingston detector.
参考文献：
[1] Zhi-Chao Zhao, Xiaolin Liu, Zhoujian Cao and Xiaokai He, Gravitational wave memory of the binary black hole events in GWTC-2, Physical Review D 104, 064056 (2021).
[2] Xiaolin Liu, Xiaokai He, and Zhoujian Cao, Accurate calculation of gravitational wave memory, Physical Review D 103, 043005 (2021).
[3] Zhoujian Cao, Wen-Biao Han, Inspiral-merger-ringdown (2, 0) mode waveforms for aligned-spin black-hole binaries, Classical and Quantum Gravity 33, 155011 (2016).
报告人简介：
曹周键，北京师范大学教授。北京师范大学本科、博士，2006年被中国科学院数学与系统科学研究院聘为助理研究员，2011年被聘为副研究员，2017年被北京师范大学天文系聘为教授。曹周键专门从事引力波天文学特别是数值相对论的研究，是正在实施的国家自然科学基金委引力波重大项目的“数值相对论和引力波建模”课题负责人。曹周键与合作者一起建立和改进了数值相对论计算方法Z4c，已被国际数值相对论界众多数值相对论小组使用。他们完成和发展了中国完全独立自主的数值相对论软件AMSS-NCKU，为国内同行提供了数值相对论研究的工具。他们还建立了椭圆轨道双黑洞并合系统旋进-并合-铃宕完备引力波模型SEOBNRE，为椭圆轨道双星系统的引力波数据处理准备好了立刻可用的引力波模板。
报告链接：
https://www.bilibili.com/video/BV1144y1x7S5?spm_id_from=333.999.0.0
