Merging galaxies produce outliers from the fundamental metallicity relation

From a large sample of ≈170 000 local SDSS (Sloan Digital Sky Survey) galaxies, we find that the fundamental metallicity relation (FMR) has an overabundance of outliers, compared to what would be expected from a Gaussian distribution of residuals, with significantly lower metallicities than predicted from their stellar mass and star formation rate (SFR). This low-metallicity population has lower s...