Shanghai Astronomical Observatory Astrophysics Colloquium

Title：Observational Signatures of Compact Object Mergers in Active Galactic Nuclei

Speaker：Hiromichi Tagawa (SHAO)

Time：3:00 pm March 21th (Thursday)

Tencent Meeting：42915400486 password: 6360

Location: Lecture Hall, 3rd floor

Report in English

Abstract：

The detection of gravitational waves (GWs) from merging binary black holes (BHs) and neutron stars has marked the dawn of a new era in astronomical and physical research. To gain a deeper understanding of the processes involved and to explore potential scientific implications, it is crucial to comprehend the astrophysical origins of these merging phenomena. One promising hypothesis relating to the origins of GWs is the mergers taking place within Active Galactic Nuclei (AGN) disks, where various intriguing phenomena are predicted to occur. However, the current challenge lies in the absence of clear-cut signatures that can effectively distinguish between different merging environments. One proposed method to differentiate between models is by analyzing the orbital eccentricities of merging binaries. Furthermore, another possible indicator of AGN merger environments is the electromagnetic radiation emitted by post-merger accreting BHs. In this presentation, I aim to outline the promising pathways for BH mergers and investigate potential indicators of mergers within AGN disks.

CV：He holds the position of research associate professor in the Gravitational Wave and Relativistic Fundamental Astronomy group at SHAO. Previously, he served as a project assistant professor at the National Astronomical Observatory of Japan in 2023 and held postdoctoral positions at Columbia University (2022-2023), Tohoku University (2020-2022), and Eotvos University (2017-2020). He earned his PhD in Astrophysics from Tokyo University in 2017.

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