English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

(abridged) We present deep spectroscopy of a large sample of low-metallicityemission-line galaxies. The main goal of this study is to derive elementabundances in these low-metallicity galaxies. We analyze 121 VLT spectra of HIIregions in 46 low-metallicity emission-line galaxies. 83 of these spectra arearchival VLT/FORS1+UVES spectra of HII regions in 31 low-metallicityemission-line galaxies that are studied for the first time with standard directmethods to determine the electron temperatures, the electron number densities,and the chemical abundances. The oxygen abundance of the sample lies in therange 12 + log O/H = 7.2-8.4. The Ne/O ratio increases with increasing oxygenabundance. The Fe/O ratio decreases from roughly solar at the lowestmetallicities to about one tenth of solar, indicating that the degree ofdepletion of iron into dust grains depends on metallicity. The N/O ratio inextremely low-metallicity galaxies with 12+logO/H<7.5 shows a slight increasewith decreasing oxygen abundance. We present the first empirical relationbetween the electron temperature derived from [SIII]6312/9069 or [NII]5755/6583and the one derived from [OIII]4363/(4959+5007) in low-metallicity galaxies. Ina number of objects, the abundances of C^++ and O^++ could be derived fromrecombination lines. Our study confirms the discrepancy between abundancesfound from recombination lines (RLs) and collisionally excited lines (CELs) andthat C/O increases with O/H.

VLT spectroscopy of low-metallicity emission-line galaxies: abundance patterns and abundance discrepancies