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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The JWST is allowing new measurements of gas-phase metallicities in galaxiesbetween cosmic noon and cosmic dawn through observations of multiple rest-frameoptical/ultraviolet [OIII], [OII], and hydrogen Balmer series lines. The mostrobust approach to such measurements uses luminosity ratios between the excitedauroral transition, [OIII] 4364A, and the lower [OIII] 5008A/4960A lines todetermine the gas temperature. The ratio of the luminosities in the lattertransitions to those in hydrogen Balmer series lines then yield relativelyclean metallicity estimates. In the absence of detection of the, often faint,[OIII] auroral line, however, the ratios of various [OIII], [OII], [NII], andBalmer lines are instead used to determine metallicities. Here we present arefined approach for extracting metallicities from these ``strong linediagnostics''. Our method exploits empirical correlations between thetemperature of OIII/OII regions and gas-phase metallicity, which lie close totheoretical expectations from thermal equilibrium calculations. We then show,from first principles, how to extract metallicities from traditional strongline diagnostics, R2, R3, R23, O3O2, and N2O2. We show that these ratios dependalso on ionization correction factors, but that these can be determinedself-consistently along with the metallicities. We quantify the success of ourmethod using metallicities derived from galaxies with auroral linedeterminations and show that it generally works better than previous empiricalapproaches. The scatter in the observed line ratios and redshift evolution arelargely explained by O3O2 variations. We provide publicly available routinesfor extracting metallicities from strong line diagnostics using ourmethodology.

Analytical strong line diagnostics and their redshift evolution