On the electron temperatures in high-metallicity H ii regions
2009 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 398, no 1, 485-496 p.Article in journal (Refereed) Published
The electron temperatures of high-metallicity [12 + log (O/H) > 8.2] H ii regions have been studied. The empirical flux-flux relations which express the nebular-to-auroral [O iii] line ratio Q(3,O) (as well as the nebular-to-auroral [O ii] line ratio Q(2,O), and the nebular-to-auroral [N ii] line ratio Q(2,N)) in terms of the nebular R-3 and R-2 line fluxes in spectra of high-metallicity H ii regions are derived, and the electron temperatures t(3,O), t(2,O) and t(2,N) in a number of extragalactic H ii regions are also determined. Furthermore, the t(2)- t(3) diagram is discussed. It is found that there is a one-to-one correspondence between t(2) and t(3) electron temperatures for H ii regions with a weak nebular R-3 lines (log R-3 less than or similar to 0.5). The derived t(2,N)-t(3,O) relation for these H ii regions is similar to commonly used t(2)-t(3) relations. The H ii regions with a strong nebular R-3 line flux (log R-3 greater than or similar to 0.5) do not follow this relation. A discrepancy between t(2,N) and t(2,O) temperatures is found, being the t(2,N) temperatures systematically lower than the t(2,O) ones. The differences are small at low electron temperatures, and increase with increasing electron temperatures up to 10 per cent at t = 1. The uncertainties in the atomic data may be the cause of this discrepancy.
Place, publisher, year, edition, pages
2009. Vol. 398, no 1, 485-496 p.
ISM: abundances, H ii regions, galaxies: abundances
IdentifiersURN: urn:nbn:se:uu:diva-128298DOI: 10.1111/j.1365-2966.2009.15182.xISI: 000269136800060OAI: oai:DiVA.org:uu-128298DiVA: diva2:331138