2023/06/21 by Jackson Sipple, Sipple, Jackson, Adam Lidz +1 · 5 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2306.12087
openalex publication_date 2023/06/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A recent ultraviolet luminosity function (UVLF) analysis in the Hubble Frontier Fields, behind foreground lensing clusters, has helped solidify estimates of the faint-end of the z ∼ 5-9 UVLF at up to five magnitudes fainter than in the field. These measurements provide valuable information regarding the role of low luminosity galaxies in reionizing the universe and can help in calibrating expectations for JWST observations. We fit a semi-empirical model to the lensed and previous UVLF data from Hubble. This fit constrains the average star formation efficiency (SFE) during reionization, with the lensed UVLF measurements probing halo mass scales as small as M ∼ 2 × 109 \rm M_\odot. The implied trend of SFE with halo mass is broadly consistent with an extrapolation from previous inferences at M \gtrsim 1010 \rm M_\odot, although the joint data prefer a shallower SFE. This preference, however, is partly subject to systematic uncertainties in the lensed measurements. Near z ∼ 6 we find that the SFE peaks at ∼ 20 % between ∼ 1011-1012 \rm M_\odot. Our best fit model is consistent with Planck 2018 determinations of the electron scattering optical depth, and most current reionization history measurements, provided the escape fraction of ionizing photons is f\rm esc ∼ 10-20%. The joint UVLF accounts for nearly 80% of the ionizing photon budget at z ∼ 8. Finally, we show that recent JWST UVLF estimates at z \gtrsim 11 require strong departures from the redshift evolution suggested by the Hubble data.