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- Title
- The influence of galaxy mergers, black hole growth, and gas processes on the evolution of the stellar mass-gas metallicity relation of galaxies in different cosmic environments
- KIAS Author
- Singh, Ankit;Pichon, Christophe
- Journal
- MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2026
- Archive
-
- Abstract
- We study the impact of supermassive black hole (M-SMBH) growth, , major and minor galaxy mergers, and gas processes, on the average gas metallicity of galaxies within the Horizon Run 5 simulation, with the aim to uncover which of these processes drive the scatter in the gas metallicity-stellar mass relation (MZR) at different redshifts in nodes, filaments and voids. At z= 5, minor mergers produce the largest differential in log[Zg /Z(Theta)] where all environments display a maximum 0.22 dex increase in the average log[Z(g) /Z(Theta)] compared to non-merging galaxies. The node population also displays a consistent 0.1 dex negative offset in d log[Zg /Z(Theta)], the residual z(g )from the total MZR of all galaxies, across all redshifts, whilst filament and void galaxies show a smaller offset. Major mergers show little influence on these same properties. This suggests minor mergers regulate metallicity and contribute to galaxy mass growth concurrently, accelerating chemical evolution post merger. Between z = 1-3, a high leads to a larger negative offset in log[Z(g)/Z(Theta)] for all environments. Here, node galaxies show the largest negative offset of approximately 0.25 dex, suggesting that AGN-driven gas removal may contribute to the MZR scatter at intermediate times. Finally, galaxies with low M-gas / M-tot show increased log[Z(g)/Z(Theta)] across all redshifts and environments, again a 0.25 dex maximum for node galaxies. These galaxies also spike in log[Z(g)/Z(Theta)] at late times, below . At this time, galaxies in the nodes show negative (M-gas) whilst also showing the largest values we observe of 0.2 dex, suggesting the importance of the balance between gas accretion and starvation in driving MZR scatter at low redshifts.
