Oral Presentation

Rapid Growth of Supermassive Black Holes through Accreting Molecular Gas during Major Mergers

Author(s): Chi-Hong Lin, Ke-Jung Chen, Chorng-Yuan Hwang

Presenter: Chi-Hong Lin (ASIAA)

Galaxy mergers represent galaxy pairs undergoing a significant transitional stage. The corresponding star formation rates and the mass of supermassive black holes (SMBHs) inside galaxies may change during this span. However, unlike objects in time-domain astronomy, the duration of galaxy mergers can take up to a few billion years beyond our observability. Hence, the way to study the fundamental physics of galaxy mergers is by utilizing numerical simulations. The hydrodynamics simulation code we used is called GIZMO, which is appropriate to model complicated galaxy interactions and SMBH growth processes. We simulate these galaxies with physical parameters based on the observational results (e.g., Gaia) and run our simulations on the NERSC's supercomputer, Cori. Our simulations consider gas physics, star formation, the empirical spiral-galaxy model, and the detailed physics of SMBH. We investigate the co-evolution between SMBHs and their host galaxies by examining the SMBH growth, bulge size, and star formation activity. We found that molecular clouds drive a rapid SMBH growth and trigger a starburst during major mergers. To confirm this finding, we also discuss the gas temperature and density around SMBHs, which help us to understand the formation of those "heavy monsters."