Colloquium on Apr. 15, 2025

The Path to Coalescence: Supermassive Black Hole Binaries in Galaxy Mergers

Speaker: Shihong Liao (NAOC)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Tuesday, Apr. 15, 2025

Abstract:

Supermassive black hole (SMBH) binaries within galaxy mergers are the primary target for space-borne gravitational wave (GW) observatories. Understanding the coalescence process of SMBHs in a cosmological framework is pivotal for accurate GW predictions. However, traditional cosmological hydrodynamical simulations often merge SMBHs instantaneously at kpc or sub-kpc separation scales due to resolution limitations, leading to significant uncertainty in estimating SMBH coalescence time-scales. In this talk, I will introduce the KETJU code, our newly developed numerical tool capable of simultaneously following galaxy (hydro-)dynamics and resolving SMBH dynamics with post-Newtonian corrections down to a few tens of Schwarzschild radii. Based on this novel numerical tool, our on-going RABBITS (Resolving supermAssive Black hole Binaries In galacTic hydrodynamical Simulations) series study will improve the estimation of the SMBH merger time-scales and ultimately enhance our predictions of GW event rates.

Report PPT:  SWIFAR_Shihong Liao.pdf