The mass-metallicity relation of Lyman-break analogues and its dependence on galaxy properties

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We investigate the mass-metallicity relation and its dependence on galaxy physical properties with a sample of 703 Lyman-break analogues (LBAs) in local Universe, which have similar properties to high redshift star-forming galaxies. The sample is selected according to luminosity, L()>10⁴¹.⁸ ergs⁻¹, and surface brightness, I()>10⁴⁰.⁵ ergs⁻¹kpc⁻², criteria. The mass-metallicity relation of LBAs harmoniously agrees with that of star-forming galaxies at z 1.4-1.7 in stellar mass range of 10⁸.⁵M<M*<10¹¹M. The relation between stellar mass, metallicity and star formation rate of our sample is roughly consistent with the local fundamental metallicity relation. We find that the mass-metallicity relation shows a strong correlation with the 4000Å break; galaxies with higher 4000Å break typically have higher metallicity at a fixed mass, by 0.06 dex in average. This trend is independent of the methodology of metallicity. We also use the metallicity estimated by T e-method to confirm it. The scatter in mass-metallicity relation can be reduced from 0.091 to 0.077 dex by a three-dimensional relation between stellar mass, metallicity and 4000Å break. The reduction of scatter in mass-metallicity relation suggests that the galaxy stellar age plays an important role as the second parameter in the mass-metallicity relation of LBAs.