The extension of the fundamental metallicity relation beyond the BPT star-forming sequence: Evidence for both gas accretion and starvation

The fundamental metallicity relation (FMR) of galaxies is a 3D between the gas-phase metallicity, stellar mass and star-formation rate (SFR). It has been studied so far only for identified as star-forming (SF) on BPT diagrams (BPT-SF), but not with LI(N)ER/AGN classification (BPT-non-SF), mainly due to lack diagnostics estimating their metallicities in latter cases. We extend FMR BPT-non-SF galaxies. To this end, we exploit recent nebular line empirical calibrations derived specifically classified non-SF diagrams. Moreover, study an alternative representation where consider offsets SFR respect Main Sequence (MS) find that higher than MS are more metal-poor counterparts MS, which interpreted terms gas accretion, boosting star formation diluting metallicity. Low-mass below (i.e. towards quiescence) have counterparts, starvation, suppression fresh supply) hampering reducing dilution effect, hence resulting level internal chemical enrichment. Massive much closer lower expected from metallicities; result suggests scenario massive nearly-quiescent LI(N)ER-like emission recently accreted circum/intergalactic medium.