The impact of minor mergers to galaxy mass assembly – insights from IllustrisTNG and JWST

Galaxy mergers play an important role in the assembly history of galaxies, yet their impact on mass evolution and star formation remains an open question. Large-scale cosmological simulations and recent JWST results have enabled a deeper investigation of how mergers shape the baryonic components of galaxies over cosmic time. Using IllustrisTNG simulations, we examined the mass growth and star formation history of galaxy mergers across redshifts 0 < z < 15 and compared our findings with JWST observations. Our analysis of merger trees from the TNG100-1 and TNG300-1 simulation runs reveals that merger events are associated with mass growth and an increased star formation rate in descendant galaxies. In my talk, I provide a quantitative assessment of how minor mergers, where the mass ratio is below 1:10, contribute to mass assembly and star formation, highlighting their importance in galaxy evolution.