On the central abundances of Active Galactic Nuclei and Star-forming Galaxies

• Autores: Dors Jr., O. L.; Cardaci, Mónica Viviana; Hägele, Guillermo Federico; Rodrigues, I.; Grebel, E. K.; Pilyugin, L. S.; Freitas Lemes, P.; Krabbe, A. C.
• Año de publicación: 2015
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Astronomía; Física; Ciencias Naturales; Ciencias Exactas; Evolution of galaxies; Abundances; Formation of galaxies; Interstellar medium
• Institución: Universidad Nacional de La Plata

We examine the relation between oxygen abundances in the narrow-line regions (NLRs) of active galactic nuclei (AGNs) estimated from the optical emission lines through the strong-line method (the theoretical calibration of Storchi-Bergmann et al. 1998), via the direct Te-method, and the central intersect abundances in the host galaxies determined from the radial abundance gradients. We found that the T_e-method underestimates the oxygen abundances by up to ∼2 dex (with average value of ~0.8 dex) compared to the abundances derived through the strong-line method. This con- firms the existence of the so-called ?temperature problem? in AGNs. We also found that the abundances in the centres of galaxies obtained from their spectra trough the strong-line method are close to or slightly lower than the central intersect abun- dances estimated from the radial abundance gradient both in AGNs and Star-forming galaxies. The oxygen abundance of the NLR is usually lower than the maximum at- tainable abundance in galaxies (~2 times the solar value). This suggests that there is no extraordinary chemical enrichment of the NLRs of AGNs.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto de Astrofísica de La Plata