A fundamental metallicity relation for galaxies at z = 0.84-1.47 from HiZELS

We obtained Subaru FMOS observations of Hα emitting galaxies selected from the HiZELS, to investigate the relationship between stellarmass, metallicity and star formation rate (SFR) at z = 0.84-1.47, for comparison with the fundamental metallicity relation seen at low redshift. Our findings demonstrate, for the first time with a homogeneously selected sample, that a relationship exists for typical star-forming galaxies at z ~ 1-1.5 and that it is surprisingly similar to that seen locally. Therefore, star-forming galaxies at z ~ 1-1.5 are no less metal abundant than galaxies of similar mass and SFR at z ~ 0.1, contrary to claims from some earlier studies.We conclude that the bulk of the metal enrichment for this star-forming galaxy population takes place in the 4 Gyr before z ~ 1.5. We fit a new mass-metallicity-SFR plane to our data which is consistent with other high-redshift studies. However, there is some evidence that the mass-metallicity component of this high-redshift plane is flattened, at all SFR, compared with z ~ 0.1, suggesting that processes such as star formation-driven winds, thought to remove enriched gas from low-mass haloes, are yet to have as large an impact at this early epoch. The negative slope of the SFR-metallicity relation from this new plane is consistent with the picture that the elevation in the SFR of typical galaxies at z≳ 1 is fuelled by the inflow of metal-poor gas and not major merging.