Metallicity Estimates with SDSS–DR6

Abstract

We present a study of the metallicity of 20268 galaxies from the Sloan Digital Sky Survey---Data Release 6 (SDSS-DR6)---using the R 23 method, and derive analytical calibrations from several metallicity-sensitive line ratios: [Nii] $λ$6583/H$α$, [Oiii] $λ$5007/[Nii] $λ$6583, [Nii] $λ$6583/[Oii] $λ$3727, [Nii] $λ$6583/ [Sii] $λ$$λ$6717, 6731, [Sii] $λ$$λ$6717, 6731/H$α$, and [Oiii] $λ$$λ$4959, 5007/H$β$. We have performed the study for the resdshift interval (0.04-0.1) for all the Sloan survey release. This is the first part of a more complete work which aims to study the metallicity dependences of the star-forming galaxies in the Local Universe.