Digging into the Ultraviolet Luminosity Functions of Galaxies at High Redshifts: Galaxies Evolution, Reionization, and Cosmological Parameters

Abstract

Thanks to the successful performance of the James Webb Space Telescope, our understanding of the epoch of reionization of the Universe has been advanced. The ultraviolet luminosity functions (UV LFs) of galaxies span a wide range of redshifts, not only revealing the connection between galaxies and dark matter (DM) halos but also providing information during reionization. In this work, we develop a model connecting galaxy counts and apparent magnitude based on UV LFs, which incorporates redshift-dependent star formation efficiency (SFE) and corrections for dust attenuation. By synthesizing some observations across the redshift range of 4 ≤ z ≤ 10 from various galaxy surveys, we discern the evolving SFE with increasing redshift and DM halo mass through model fitting. Subsequent analyses indicate that the Thomson scattering optical depth was τe=0.054‑0.003+0.001 and the epoch of reionization started (ended) at z=18.8‑6.0+7.2 ( z=5.3‑1.0+0.8 ), which is insensitive to the choice of the truncated magnitude of the UV LFs. Incorporating additional data sets and some reasonable constraints, the amplitude of matter perturbation is found to be σ ₈ = 0.80 ± 0.05, which is consistent with the standard ΛCDM model. Future galaxy surveys and the dynamical simulations of galaxy evolution will break the degeneracy between SFE and cosmological parameters, improving the accuracy and the precision of the UV LF model further.