A new approach to estimate oxygen abundance. The MRC calibrator

Several studies use the emission lines fluxes of the star forming galaxies to derive the gas-phase metallicity by applying the so-called strong-line methods. These metallicity indicators are empirically calibrated using direct abundance measurements. Our main goal in this study is to present a new approach to derive oxygen abundances using all the possible combinations of strong line ratios sensitive to the metallicity, covering a wide range interval of this parameter, through a large compilation of HII regions with Te-based estimations (Marino et al. 2013). Our method called MRC (Multiple Ratio Calibrator) provides with a calibration with a systematic error of 0.13 dex. We also present a comparison between this new method and the O3N2, N2 calibrations (Marino et al. 2013), the ONS method (Pilyugin et al. 2010) and the C method (Pilyugin et al. 2012). Furthermore, we perform an analysis of the abundance gradient of the galaxy NGC628 confirming previous works.