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

The most robust way for determining the distance of quasar absorptionoutflows is the use of troughs from ionic excited states. The column densityratio between the excited and resonance states yields the outflow numberdensity. Combined with a knowledge of the outflow's ionization parameter, adistance from the central source (R) can be determined. Here we report resultsfrom two surveys targeting outflows that show troughs from S IV. One surveyincludes 1091 SDSS and BOSS quasar spectra, and the other includeshigher-quality spectra of 13 quasars observed with the Very Large Telescope.Our S IV samples include 38 broad absorption line (BAL) outflows, and fourmini-BAL outflows. The S IV is formed in the same physical region of theoutflow as the canonical outflow-identifying species C IV. Our results showthat S IV absorption is only detected in 25% of C IV BAL outflows. The smallerdetection fraction is due to the higher total column density ($N_H$) needed todetect S IV absorption. Since R empirically anticorrelates with $N_H$ theresults of these surveys can be extrapolated to C IV quasar outflows with lower$N_H$ as well. We find that at least 50% of quasar outflows are at distanceslarger than 100 pc from the central source, and at least 12% are at distanceslarger than 1000 pc. These results have profound implications for the study ofthe origin and acceleration mechanism of quasar outflows and their effects onthe host galaxy.

Evidence that 50% of BALQSO Outflows Are Situated at Least 100 pc from the Central Source