Clues to the Origin of the Mass-Metallicity Relation: Dependence on Star Formation Rate and Galaxy Size

摘要

We use a sample of 43,690 galaxies selected from the Sloan Digital Sky SurveyData Release 4 to study the systematic effects of specific star formation rate(SSFR) and galaxy size (as measured by the half light radius, r_h) on themass-metallicity relation. We find that galaxies with high SSFR or large r_hfor their stellar mass have systematically lower gas phase-metallicities (by upto 0.2 dex) than galaxies with low SSFR or small r_h. We discuss possibleorigins for these dependencies, including galactic winds/outflows, abundancegradients, environment and star formation rate efficiencies.