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

A toy model is developed to understand how the spatial distribution offluorescent emitters in the vicinity of bright quasars could be affected by thegeometry of the quasar bi-conical radiation field and by its lifetime. Themodel is then applied to the distribution of high equivalent width Lyman$\alpha$ emitters (with rest-frame equivalent widths above 100 A, thresholdused in e.g. Trainor & Steidel, 2013) identified in a deep narrow-band 36x36arcmin$^2$ image centered on the luminous quasar Q0420-388. These emitters arefound to the edge of the field and show some evidence of an azimuthal asymmetryon the sky of the type expected if the quasar is radiating in a bipolar cone.If these sources are being fluorescently illuminated by the quasar, the twomost distant objects require a lifetime of at least 15 Myr for an opening angleof 60 degrees or more, increasing to more than 40 Myr if the opening angle isreduced to a minimum 30 degrees. However, few of the other expected signaturesof boosted fluorescence are seen at the current survey limits, e.g. a fall offin Lyman $\alpha$ brightness, or equivalent width, with distance. Furthermore,to have most of the Lyman $\alpha$ emission of the two distant sources to befluorescently boosted would require the quasar to have been significantlybrighter in the past. This suggests that these particular sources may not befluorescent, invalidating the above lifetime constraints. This would cast doubton the use of this relatively low equivalent width threshold and thus on thelifetime analysis in Trainor & Steidel (2013).

Constraining the lifetime and opening angle of quasars using fluorescent Lyman $\alpha$ emission: the case of Q0420-388