Astraeus V: the emergence and evolution of metallicity scaling relations during the epoch of reionization

ABSTRACT In this work, we have implemented a detailed physical model of galaxy chemical enrichment into the Astraeus (seminumerical rAdiative tranSfer coupling formaTion and Reionization in N-body dark matter simUlationS) framework which couples formation reionization first billion years. Simulating galaxies spanning over 2.5 orders magnitude halo mass with $M_{\rm h} \sim 10^{8.9}{-}10^{11.5}\,{\rm M_\odot}$ ($M_{\rm 10^{8.9}{-}10^{12.8}\rm M_\odot$) at z ? 10 (5), find: (i) smooth accretion metal-poor gas from intergalactic medium (IGM) plays key role diluting interstellar metallicity is effectively restored due to self-enrichment star formation; (ii) redshift averaged gas-mass loading factor that depends on stellar as $\eta _{\rm g} \approx 1.38 ({M_*}/{10^{10}\, {\rm \rm M_\odot }})^{-0.43}$; (iii) mass–metallicity relation already place shows no evolution down 5; (iv) for given mass, decreases an increase rate (SFR); (v) properties gas-phase (in units 12 + log(O/H), SFR are linked through high-redshift fundamental plane (HFPZ) provide functional form; (vi) mass–metallicity–SFR relations independent radiative feedback $M_* {\,\, \buildrel\gt \over \,\,}10^{6.5}\rm M_\odot$ galaxies; (vii) while low-mass \buildrel\lt \,\,}10^9\,\rm contributors metal budget IGM early times, higher haloes about 50 per cent lower redshifts.