Predicted yield and detectability of GW events from the IllustrisTNG simulations

The forthcoming generation of space-based gravitational wave (GW) observatories promises robust capabilities for multi-bandwidth measurements, particularly for the study of supermassive black holes (SMBHs). In this research, we employ the IllustrisTNG simulation to investigate GW signals originating from SMBHs. Our approach involves extracting the merger history of black holes (BHs) from the simulation data and utilizing a phenomenological waveform model to calculate the GW strains, signal-to-noise ratios and event rates. Notably, detectors like LISA, Taiji, and Tianqin demonstrate the potential to detect SMBHs with masses exceeding approximately 10 6 M ⨀ , and exhibit the capability to detect one merger in the Merger-Ringdown phase and one merger in the Inspiral phase annually, at redshifts reaching up to z ∼6.