The metallicity evolution of star-forming galaxies from redshift 0 to 3: Combining magnitude-limited survey with gravitational lensing

We present a comprehensive observational study of the gas-phase metallicity of star-forming galaxies from z ∼ 0 → 3. We combine our new sample of gravitationally lensed galaxies with existing lensed and non-lensed samples to conduct a large investigation into the mass-metallicity (MZ) relation at z > 1. We apply a self-consistent metallicity calibration scheme to investigate the metallicity evolution of star-forming galaxies as a function of redshift. The lensing magnification ensures that our sample spans an unprecedented range of stellar mass (3 × 10⁷ to 6 × 10¹⁰ M _⊙). We find that at the median redshift of z = 2.07, the median metallicity of the lensed sample is 0.35 dex lower than the local SDSS star-forming galaxies and 0.18 dex lower than the z ∼ 0.8 DEEP2 galaxies. We also present the z ∼ 2 MZ relation using 19 lensed galaxies. A more rapid evolution is seen between z ∼ 1 → 3 than z ∼ 0 → 1 for the high-mass galaxies (10^9.5 M_⊙ < M* < 10¹¹ M_⊙), with almost twice as much enrichment between z ∼ 1 → 3 than between z ∼ 1 → 0. We compare this evolution with the most recent cosmological hydrodynamic simulations with momentum-driven winds. We find that the model metallicity is consistent with the observed metallicity within the observational error for the low-mass bins. However, for higher masses, the model overpredicts the metallicity at all redshifts. The overprediction is most significant in the highest mass bin of 10¹⁰-10¹¹ M_⊙.