New quantitative nitrogen abundance estimations in a sample of Seyfert 2 Active Galactic Nuclei

Abstract

We obtained new quantitative determinations of the nitrogen abundance and a consistent relation between nitrogen and oxygen abundances for a sample of Seyfert 2 galaxies located at redshift $z<0.1$. We carried out this analysis using the Cloudy code to build detailed photoionization models. We were able to reproduce observed optical narrow emission line intensities for 44 sources compiled from the literature. Our results show that Seyfert 2 nuclei have nitrogen abundances ranging from $\sim 0.3$ to $\sim 7.5$ times the solar value. We derived the relation $\log (N/H)=1.05(\pm 0.09)\times [\log (O/H)]-0.35(\pm 0.33$). Results for N/O vs. O/H abundance ratios derived for Seyfert 2 galaxies are in consonance with those recently derived for a sample of extragalactic disk HII regions with high metallicity.

Accepted for publication in MNRAS LETTER. 6 pages. 4 figures

References in corpus (5)

• The 2013 Release of Cloudy
• Emission-line Diagnostics of Low Metallicity AGN
• Precision abundance analysis of bright HII galaxies
• Probing the Physics of Narrow Line Regions in Active Galaxies II: The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)
• New metallicity calibration for Seyfert 2 galaxies based on the N2O2 index

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