题目： Implications of Pulsar Timing Array Observations
报告人：龚云贵 教授
邀请人： 李瑾
时间： 2024年1月12号（星期五）上午9：30
地点： LE201
报告摘要: Gravitational waves (GWs) opened a new window to uncover some of the universe’s biggest mysteries and became a game-changer for astronomy. Strong evidence of the existence of the stochastic gravitational wave background (SGWB) has been reported recently by the Pulsar Timing Array (PTA) observations. While supermassive black hole binaries (SMBHBs) present a plausible explanation for the observed signal, the predicted spectral index for one-sided power spectral density of SGWB is almost 2sigma away from the observation. We discuss the modifications arising from extra scalar or vector radiations to the characteristic dimensionless strain of gravitational waves from SMBHBs and explore the possibility of detecting charges carried by supermassive black holes in modified gravity and new fundamental fields. On the other hand, scalar induced secondary gravitational waves (SIGWs) from some particular models fit the signals detected by PTAs better than GWs from SMBHBs, so we also test the consistency of the data with the universal behavior of infrared parts of SIGWs in a somewhat model-independent way.
报告人简介:龚云贵，华中科技大学/宁波大学教授，美国贝勒大学客座教授。1991年于华中理工大学获得学士学位，1994年在中国科学院理论物理研究所获得硕士学位，2001年获得美国德克萨斯州立大学奥斯汀分校博士。主要从事相对论引力与宇宙学的研究工作。在Nature Astronomy, PRL等国际高水平学术期刊上发表了150余篇学术论文，出版宇宙学教材一部，发表的学术论文在高能数据库inspirehep中被引用7900余次，其中17篇论文被引用超过100次，h指数为46，入选了全球前10万（前2%）科学家、2020及2022中国高被引学者。主持了包括国家重点研发课题、自然科学基金重点项目在内的多项国家及省部级科研项目。先后荣获教育部新世纪优秀人才计划、中国侨界双百贡献奖（创新人才奖）、重庆市自然科学一等奖等奖项及荣誉称号。
