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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Outflows are believed to be ubiquitous and fundamentally important in activegalaxies. Despite their importance, key physical properties of outflows remainpoorly unconstrained; this severely limits study of the acceleration process.It is especially difficult to constrain the column density since most of thelines are saturated. However, column densities can be measured using ions thatare expected to be relatively rare in the gas, since they are least likely tobe saturated. Phosphorus, specifically the PV doublet at 1118 and 1128A, isgenerally regarded as a useful probe of high column densities because of itslow abundance. We have found that the metastable neutral helium triplet is anequally valuable probe of high column densities in BALQSOs. The significantadvantage is that it can be observed in the infrared (HeI*10830) and theoptical (HeI*3889) bands from the ground in low-redshift (z<1.2) objects.  We report the discovery of the first HeI*10830 BALQSO FBQS J1151+3822, anddiscuss constraints on the column density obtained from the optical and IR HeI*lines. In addition, a new observation revealing MgII and FeII absorptionprovides further constraints, and Cloudy modeling of HeI*, MgII, and FeIIsuggests that the difference between LoBALs and FeLoBALs is column densityalong the line of sight.

Probing High-Column Outflows in BALQSOs Using Metastable Helium