Mass-metallicity relation for local star-forming galaxies

Abstract

We investigate the evolution of the mass-metallicity (M-Z) relation with a large sample of53 444 star-forming galaxies (SFGs) at 0.04 < z < 0.12, selected from the catalogue ofMax-Planck-Institute for Astrophysics-John Hopkins University (MPA-JHU) emission-linemeasurements for the Sloan Digital Sky Survey Data Release 7. Regarding the sample ofSFGs, we correct the observational bias and raise the aperture covering fractions to check thereliability of the metallicity evolution. (i) We show that the redshift evolution of the log (Hα)and log([O III]) luminosities is displayed in our sample. (ii) We find the metallicity evolutionof ~0.15 dex at log(M*/M⊙) ~ 9.3 in SFGs at 0.04 < z < 0.12. (iii) After applying theluminosity thresholds of log (LHα) > 41.0 and log(L[O III]) > 39.7, we find that the metallicityevolution is shown well, and that the evolution of the star formation rate (SFR) is still shownwell under the latter luminosity threshold, but the evolution is not observed under the former.(iv) The evolution of the M-Z relation seems to disappear at about log(M*/M⊙) > 10.0after applying the luminosity threshold of log (LHα) > 41.0 or log(L[[O III]) > 39.7. (v) We finda = 0.09 and a = 0.07 in the equation, μ = logM* - α log(SFR), for log (LHα) > 41.0 andlog(L[O III]) > 39.7 samples, respectively, and these imply that the evolution of the M-Z relationmight have a weaker dependence on the SFR in our sample.