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 4D Eigenvector 1 sequence has proven to be a highly effective tool fororganizing observational and physical properties of type 1 active galacticnuclei (AGN). In this paper, we present multiple measurements of metallicityfor the broad line region gas, from new or previously published data. Wedemonstrate a consistent trend along the optical plane of the E1 (also known asthe quasar main sequence), defined by the line width of H$\beta$ and by aparameter measuring the prominence of singly-ionized iron emission. The trendinvolves an increase from sub-solar metallicity in correspondence with extremePopulation B (weak FeII emission, large H$\beta$ FWHM) to metallicity severaltens the solar value in correspondence with extreme Population A (very strongFeII optical emission, narrower H$\beta$ profiles). The data establish themetallicity as a correlate of the 4D E1/main sequence. If the very highmetallicity gas ($Z \gtrsim 10 Z_\odot$) is expelled from the sphere ofinfluence of the central black hole, as indicated by the widespread evidence ofnuclear outflows and disk wind in the case of sources radiating at highEddington ratio, then it is possible that the outflows from quasars played arole in chemically enriching the host galaxy.

From sub-solar to super-solar chemical abundances along the quasar main sequence