Chemical abundances in Seyfert galaxies – IX. Helium abundance estimates

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dc.contributor.authorDors Junior, Oli Luiz
dc.contributor.authorValerdi, Mabel
dc.contributor.authorLemes, Priscila Freitas
dc.contributor.authorKrabbe, Angela Cristina
dc.contributor.authorRiffel, Rogemar André
dc.contributor.authorAmôres, Eduardo Brescansin
dc.contributor.authorRiffel, Rogério
dc.contributor.authorArmah, Mark
dc.contributor.authorMonteiro, Adriano Francisco
dc.contributor.authorOliveira Junior, Celso Benedito de
dc.date.accessioned2025-03-14T14:15:19Z
dc.date.available2025-03-14T14:15:19Z
dc.date.issued22022
dc.description.abstractFor the first time, the helium abundance relative to hydrogen (He/H), which relied on direct measurements of the electron temperature, has been derived in the narrow line regions (NLRs) from a local sample of Seyfert 2 nuclei. In view of this, optical emission line intensities [3000 < λ(Å) < 7000] of 65 local Seyfert 2 nuclei (z < 0.2), taken from Sloan Digital Sky Survey Data Release 15 and additional compilation from the literature, were considered. We used photoionization model grid to derive an Ionization Correction Factor (ICF) for the neutral helium. The application of this ICF indicates that the NLRs of Seyfert 2 present a neutral helium fraction of ∼50 per cent in relation to the total helium abundance. We find that Seyfert 2 nuclei present helium abundance ranging from 0.60 to 2.50 times the solar value, while ∼85 per cent of the sample present oversolar abundance values. The derived (He/H)–(O/H) abundance relation from the Seyfert 2 is stepper than that of star-forming regions (SFs) and this difference could be due to excess of helium injected into the interstellar medium by the winds of Wolf–Rayet stars. From a regression to zero metallicity, by using Seyfert 2 estimates combined with SFs estimates, we obtained a primordial helium mass fraction Yp = 0.2441 ± 0.0037, a value in good agreement with the one inferred from the temperature fluctuations of the cosmic microwave background by the Planck Collaboration
dc.description.physical22 p.
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.uriFAPESP (2020/16416-5, 2019/11934-0)
dc.format.mimetypePDF
dc.identifier.affiliationUniversidade do Vale do Paraíba
dc.identifier.affiliationInstituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)
dc.identifier.affiliationUniversidade Federal de Santa Maria
dc.identifier.affiliationUniversidade Estadual de Feira de Santana
dc.identifier.affiliationUniversidade Federal do Rio Grande do Sul
dc.identifier.affiliationInstituto Federal do Maranhão
dc.identifier.bibliographicCitationDORS JUNIOR, Oli Luiz et al. Chemical abundances in Seyfert galaxies – IX. Helium abundance estimates. Monthly Notices of the Royal Astronomical Society, v. 514, n. 4, p. 5506-5527, 2022. Disponível em:
dc.identifier.doi10.1093/mnras/stac1722
dc.identifier.urihttps://repositorio.univap.br/handle/123456789/697
dc.language.isoen_US
dc.publisherRoyal Astronomical Society
dc.rights.holderMonthly Notices of the Royal Astronomical Society
dc.subject.keywordGalaxies: abundances
dc.subject.keywordGalaxies: active
dc.subject.keywordGalaxies: evolution
dc.subject.keywordGalaxies: formation
dc.subject.keywordGalaxies: ISM
dc.subject.keywordGalaxies: nuclei
dc.titleChemical abundances in Seyfert galaxies – IX. Helium abundance estimates
dc.typeArtigos de Periódicos

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