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Title: Chemical abundances of Seyfert 2 AGNs – I. Comparing oxygen abundances from distinct methods using SDSS

Abstract

ABSTRACT We compare the oxygen abundance (O/H) of the narrow-line regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the effects of the use of distinct methods on the range of metallicity and on the mass–metallicity relation of active galactic nuclei (AGNs) at low redshifts (z ≲ 0.4). We used the Sloan Digital Sky Survey (SDSS) and NASA/IPAC Extragalactic Database (NED) to selected optical (3000 < λ(Å) < 7000) emission line intensities of 463 confirmed Seyfert 2 AGNs. The oxygen abundances of the NLRs were estimated using the theoretical Storchi-Bergmann et al. calibrations, the semi-empirical N2O2 calibration, the Bayesian H  ii-Chi-mistry code and the Te-method. We found that the oxygen abundance estimations via the strong-line methods differ from each other up to ∼0.8 dex, with the largest discrepancies in the low-metallicity regime ($$\rm 12+\log (O/H) \: \lesssim \: 8.5$$). We confirmed that the Te-method underestimates the oxygen abundance in NLRs, producing unreal subsolar values. We did not find any correlation between the stellar mass of the host galaxies and the metallicity of their AGNs. This result is independent of the method used to estimate Z.

Authors:
ORCiD logo [1];  [1];  [2];  [3]; ORCiD logo [4];  [4];  [1];  [1];  [5]
  1. Universidade do Vale do Paraíba. Av. Shishima Hifumi, 2911, CEP 12244-000 São José dos Campos, SP, Brazil
  2. Departamento de Física, Universidade Estadual de Feira de Santana, Av. Transnordestina, S/N, CEP 44036-900 Feira de Santana, BA, Brazil
  3. Instituto de Astrofísica de Andalucía, Camino Bajo de Huétor s/n, Aptdo. 3004, E18080-Granada, Spain
  4. Instituto de Astrofísica de La Plata, Avenida Centenario (Paseo del Bosque) S/N, B1900FWA La Plata, Argentina, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
  5. MCTIC/ Laboratório Nacional de Astrofísica, CEP 37.504-364 Itajubá, MG, Brazil
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1581037
Resource Type:
Published Article
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 492 Journal Issue: 1; Journal ID: ISSN 0035-8711
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Dors, O. L., Freitas-Lemes, P., Amôres, E. B., Pérez-Montero, E., Cardaci, M. V., Hägele, G. F., Armah, M., Krabbe, A. C., and Faúndez-Abans, M. Chemical abundances of Seyfert 2 AGNs – I. Comparing oxygen abundances from distinct methods using SDSS. United Kingdom: N. p., 2019. Web. doi:10.1093/mnras/stz3492.
Dors, O. L., Freitas-Lemes, P., Amôres, E. B., Pérez-Montero, E., Cardaci, M. V., Hägele, G. F., Armah, M., Krabbe, A. C., & Faúndez-Abans, M. Chemical abundances of Seyfert 2 AGNs – I. Comparing oxygen abundances from distinct methods using SDSS. United Kingdom. doi:10.1093/mnras/stz3492.
Dors, O. L., Freitas-Lemes, P., Amôres, E. B., Pérez-Montero, E., Cardaci, M. V., Hägele, G. F., Armah, M., Krabbe, A. C., and Faúndez-Abans, M. Tue . "Chemical abundances of Seyfert 2 AGNs – I. Comparing oxygen abundances from distinct methods using SDSS". United Kingdom. doi:10.1093/mnras/stz3492.
@article{osti_1581037,
title = {Chemical abundances of Seyfert 2 AGNs – I. Comparing oxygen abundances from distinct methods using SDSS},
author = {Dors, O. L. and Freitas-Lemes, P. and Amôres, E. B. and Pérez-Montero, E. and Cardaci, M. V. and Hägele, G. F. and Armah, M. and Krabbe, A. C. and Faúndez-Abans, M.},
abstractNote = {ABSTRACT We compare the oxygen abundance (O/H) of the narrow-line regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the effects of the use of distinct methods on the range of metallicity and on the mass–metallicity relation of active galactic nuclei (AGNs) at low redshifts (z ≲ 0.4). We used the Sloan Digital Sky Survey (SDSS) and NASA/IPAC Extragalactic Database (NED) to selected optical (3000 < λ(Å) < 7000) emission line intensities of 463 confirmed Seyfert 2 AGNs. The oxygen abundances of the NLRs were estimated using the theoretical Storchi-Bergmann et al. calibrations, the semi-empirical N2O2 calibration, the Bayesian H  ii-Chi-mistry code and the Te-method. We found that the oxygen abundance estimations via the strong-line methods differ from each other up to ∼0.8 dex, with the largest discrepancies in the low-metallicity regime ($\rm 12+\log (O/H) \: \lesssim \: 8.5$). We confirmed that the Te-method underestimates the oxygen abundance in NLRs, producing unreal subsolar values. We did not find any correlation between the stellar mass of the host galaxies and the metallicity of their AGNs. This result is independent of the method used to estimate Z.},
doi = {10.1093/mnras/stz3492},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 1,
volume = 492,
place = {United Kingdom},
year = {2019},
month = {12}
}

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