2025/03/17 by Aaron R. Rowntree, Rowntree, Aaron R., Fiorenzo Vincenzo +19
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Astronomy and Astrophysical Research #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2503.12928
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⋆ < 109.8 M\odot, 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⋆ ≈ 109.35 M\odot, 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.