Abstract：Supermassive black hole (SMBH) binaries within galaxy mergers are the primary targets for upcoming low-frequency gravitational-wave (GW) observatories. Understanding the coalescence process of SMBH binaries in a cosmological galaxy formation context is crucial for accurate GW predictions. However, traditional galaxy formation simulations, including IllustrisTNG, EAGLE, and COLIBRE, often merge SMBHs instantaneously at kpc or sub-kpc separation scales due to resolution limitations, leading to significant uncertainty in estimating SMBH coalescence timescales. In this talk, I will introduce our new numerical tools, namely the KETJU code and the RABBITS series simulations, which can simultaneously follow galaxy hydrodynamics and resolve SMBH dynamics with post-Newtonian corrections down to the GW inspiral phase. These simulations enable improved estimates of SMBH merger timescales, especially in gas-rich galaxy mergers, as well as related GW predictions, and allow us to study the impact of SMBH binaries on galaxy properties.
Bio：Dr. Shihong Liao (廖世鸿) is currently a Researcher at the National Astronomical Observatories, Chinese Academy of Sciences (NAOC). He obtained his PhD from the Chinese University of Hong Kong, and subsequently carried out postdoctoral research at NAOC and the University of Helsinki before joining NAOC as a faculty member in 2024. He was selected for the CAS Pioneer Hundred Talents Program (Category B). His research focuses on galaxy formation, supermassive black holes, and cosmological simulations.
