We study the stellar mass-gas metallicity relation (MZR) which shows a significant scatter for a fixed stellar mass. By defining global environments, nodes, filaments, and voids within the Horizon Run 5 cosmological hydrodynamical simulation, we explore when and where the enrichment of galaxies occurs, analysing key evolution parameters such as star-formation rate and changes in gas-fraction and gas-metallicity per unit time. At high redshift ( z>4.5 ), there are minimal deviations from the MZR due to environment, however, larger deviations emerge as redshift decreases. Low stellar mass galaxies in nodes, M⋆<109.8M⊙ , start showing deviations at z=3.5 , whilst other environments do not. For, z<2 , filaments and voids begin to show deviations above and below the MZR, respectively. By z=0.625 , the last epoch of HR5, deviations exist for all stellar masses and environments, with a maximum value of 0.13 dex at M⋆≈109.35M⊙ , between the median gas metallicities of node and void galaxies. To explain this environmental variance we discuss gas accretion, AGN, ram-pressure-stripping and strangulation as regulators of Zg . Concurrently, at high metallicities, for z<2 , while massive galaxies in nodes show increasing Zg and decreasing [O/Fe], void galaxies show a turnover where Zg falls with decreasing [O/Fe]. This directly points to the importance of cold-gas accretion in retaining lower Zg in massive void galaxies for z<2 , whilst its absence in nodes allowed Zg to access higher values.
The role of large-scale environment in shaping the stellar mass-gas metallicity relation across time
Vincenzo, Fiorenzo;
2026-01-01
Abstract
We study the stellar mass-gas metallicity relation (MZR) which shows a significant scatter for a fixed stellar mass. By defining global environments, nodes, filaments, and voids within the Horizon Run 5 cosmological hydrodynamical simulation, we explore when and where the enrichment of galaxies occurs, analysing key evolution parameters such as star-formation rate and changes in gas-fraction and gas-metallicity per unit time. At high redshift ( z>4.5 ), there are minimal deviations from the MZR due to environment, however, larger deviations emerge as redshift decreases. Low stellar mass galaxies in nodes, M⋆<109.8M⊙ , start showing deviations at z=3.5 , whilst other environments do not. For, z<2 , filaments and voids begin to show deviations above and below the MZR, respectively. By z=0.625 , the last epoch of HR5, deviations exist for all stellar masses and environments, with a maximum value of 0.13 dex at M⋆≈109.35M⊙ , between the median gas metallicities of node and void galaxies. To explain this environmental variance we discuss gas accretion, AGN, ram-pressure-stripping and strangulation as regulators of Zg . Concurrently, at high metallicities, for z<2 , while massive galaxies in nodes show increasing Zg and decreasing [O/Fe], void galaxies show a turnover where Zg falls with decreasing [O/Fe]. This directly points to the importance of cold-gas accretion in retaining lower Zg in massive void galaxies for z<2 , whilst its absence in nodes allowed Zg to access higher values.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
