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

[Abridged] We present a physical model for the evolution of the ultraviolet(UV) luminosity function (LF) of high-z galaxies taking into account in aself-consistent way their chemical evolution and the associated evolution ofdust extinction. The model yields good fits of the UV and Lyman-alpha LFs atz>~2. The weak evolution of both LFs between z=2 and z=6 is explained as thecombined effect of the negative evolution of the halo mass function, of theincrease with redshift of the star formation efficiency, and of dustextinction. The slope of the faint end of the UV LF is found to steepen withincreasing redshift, implying that low luminosity galaxies increasinglydominate the contribution to the UV background at higher and higher redshifts.The observed range of UV luminosities at high-z implies a minimum halo masscapable of hosting active star formation M_crit <~ 10^9.8 M_odot, consistentwith the constraints from hydrodynamical simulations. From fits of Lyman-alphaLFs plus data on the luminosity dependence of extinction and from the measuredratios of non-ionizing UV to Lyman-continuum flux density for samples of z=~3Lyman break galaxies and Lyman-alpha emitters, we derive a simple relationshipbetween the escape fraction of ionizing photons and the star formation rate,impling larger escape fraction for less massive galaxies. Galaxies alreadyrepresented in the UV LF (M_UV <~ -18) can keep the universe fully ionized upto z=~6, consistent with (uncertain) data pointing to a rapid drop of theionization degree above z~6. On the other side, the electron scattering opticaldepth, tau_es, inferred from CMB experiments favor an ionization degree closeto unity up to z=~9-10. Consistency with CMB data can be achieved if M_crit =~10^8.5 M_odot, implying that the UV LFs extend to M_UV =~ -13, although thecorresponding tau_es is still on the low side of CMB-based estimates.

A physical model for the evolving UV luminosity function of high redshift galaxies and their contribution to the cosmic reionization