The SAMI Galaxy Survey: the drivers of gas and stellar metallicity differences in galaxies

The combination of gas-phase oxygen abundances and stellar metallicities can provide us with unique insights into the metal enrichment histories galaxies. In this work, we compare measured within a 1$R_{e}$ aperture for representative sample 472 star-forming galaxies extracted from SAMI Galaxy Survey. We confirm that interstellar medium (ISM) are strongly correlated, scatter $\sim$3 times smaller than found in previous works, integrated populations generally more metal-poor ISM, especially low-mass ratio between two correlates several galaxy properties including mass, specific star formation rate, gravitational potential proxy. However, show these trends primarily consequence of: (a) different galaxies, (b) fact while trace iron enrichment, metallicity indicators calibrated to ISM. Indeed, once both converted same `element base' all our become significantly weaker. Interestingly, gas is always below value expected simple closed-box model, which requires outflows inflows play an important role history across entire mass range. This work highlights complex interplay shows how care must be taken comparing them constrain models evolution.