Chemical abundances in Seyfert galaxies – VI. Empirical abundance calibration

ABSTRACT We derived a bi-dimensional calibration between the emission-line ratios $R_{23}= ([\mathrm{ O}\, {\small {\rm II}}]\,\lambda 3726 +\lambda 3729 +[\mathrm{ O}\mathrm{ }\, III}}]\,\lambda 4959 + \lambda 5007)/\rm H\,\beta$, ${\it P}=[([\mathrm{ 4959+\lambda 5007)/{\rm H}\,\beta ]/R_{23}$ and oxygen abundance relative to hydrogen (O/H) in gas phase of Seyfert 1 2 nuclei. In view this, intensity for sample objects taken from Sloan Digital Sky Survey Data Release 7 measured by MPA/JHU group direct estimates O/H based on Te-method, adapted active galactic nuclei (AGNs), are considered. find no variation R23 observed along radii AGNs, which shows that this line ratio is good indicator class considered work. The = f(R23, P) relation produces values similar estimations via Te-method wide range metallicities [$\rm 8.0 \: \lesssim 12+\log \,(O/H) 9.2$]. Conversely star-forming regions high-metallicity regime, positive correlation trend with AGNs. This indicates hardness ionizing radiation not affected these or narrow-line significantly modified changes spectral energy distribution due metallicity variations.