4 papers
Cosmic evolution of the helium and oxygen abundances in type 2 Active Galactic Nuclei: Helium-loud AGNs
O. L. Dors, M. Armah, G. F. Hägele +14
We derive the helium and oxygen abundances in the Narrow Line Regions (NLRs) of 84 Active Galactic Nuclei (AGNs) spanning two redshift ranges: 65 objects at and 19…
Metallicity of Active Galactic Nuclei from ultraviolet and optical emission lines-II. Revisiting the metallicity calibration and its implications
O. L. Dors, C. B. Oliveira, M. V. Cardaci +7
In this study, a new semi-empirical calibration is proposed between ultraviolet emission lines (\ion{C}{iii}], \ion{C}{iv}, \ion{He}{ii}]) of…
Metallicity of Active Galactic Nuclei from ultraviolet and optical emission lines I: Carbon abundance dependence
O. L. Dors, C. B. Oliveira, M. V. Cardaci +9
Metallicity () estimates based on ultraviolet (UV) emission lines from the narrow-line regions (NLRs) of active galactic nuclei (AGNs) have been found to differ from those deriv…
Semi-empirical calibration of the oxygen abundance for LINER galaxies based on SDSS-IV MaNGA -- The case for strong and weak AGN
C. B. Oliveira, O. L. Dors, I. A. Zinchenko +5
In this paper, we present a semi-empirical calibration between the oxygen abundance and the emission-line ratio for Low Ionization Nuclear Emission Regions (LINERs). This rela…