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 cosmic ionizing emissivity from star-forming galaxies has long beenanchored to UV luminosity functions. Here we introduce an emissivity frameworkbased on Ly$\alpha$ emitters (LAEs), which naturally hones in on the subset ofgalaxies responsible for the ionizing background due to the intimate connectionbetween the production and escape of Ly$\alpha$ and LyC photons. Usingconstraints on the escape fractions of bright LAEs ($L_{\rm{Ly\alpha}}>0.2L^{*}$) at $z\approx2$ obtained from resolved Ly$\alpha$ profiles, and arguingfor their redshift-invariance, we show that: (i) quasars and LAEs togetherreproduce the relatively flat emissivity at $z\approx2-6$, which is non-trivialgiven the strong evolution in both the star-formation density and quasar numberdensity at these epochs and (ii) LAEs produce late and rapid reionizationbetween $z\approx6-9$ under plausible assumptions. Within this framework, the$>10\times$ rise in the UV population-averaged $f_{\rm{esc}}$ between$z\approx3-7$ naturally arises due to the same phenomena that drive the growingLy$\alpha$ emitter fraction with redshift. Generally, a LAE dominatedemissivity yields a peak in the distribution of the ionizing budget with UVluminosity as reported in latest simulations. Using our adopted parameters($f_{\rm{esc}}=50\%$, $\xi_{\rm{ion}}=10^{25.9}$ Hz erg$^{-1}$ for half thebright LAEs), a highly ionizing minority of galaxies with $M_{\rm UV}<-17$accounts for the entire ionizing budget from star-forming galaxies. Rapidflashes of LyC from such rare galaxies produce a "disco" ionizing background.We conclude proposing tests to further develop our suggestedLy$\alpha$-anchored formalism.

(Re)Solving Reionization with Ly{\alpha}: How Bright Ly{\alpha} Emitters account for the $z\approx2-8$ Cosmic Ionizing Background