A new tool to derive chemical abundances in Type-2 Active Galactic
  Nuclei
  We present a new tool for the analysis of the optical emission lines of the
gas in the Narrow Line Region (NLR) around Active Galactic Nuclei (AGNs). This
new tool can be used in large samples of objects in a consistent way using
different sets of optical emission-lines taking into the account possible
variations from the O/H - N/O relation. The code compares certain observed
emission-line ratios with the predictions from a large grid of photoionization
models calculated under the most usual conditions in the NLR of AGNs to
calculate the total oxygen abundance, nitrogen-to-oxygen ratio and ionization
parameter. We applied our method to a sample of Seyfert 2 galaxies with optical
emission-line fluxes from the literature. Our results confirm the high
metallicity of the objects of the sample and provide consistent values with the
direct method. The usage of models to calculate precise ICFs is mandatory when
only optical emission lines are available to derive chemical abundances using
the direct method in NLRs of AGN.
