Simulating realistic Lyman-α emitting galaxies including the effect of radiative transfer

Abstract

We present an empirical yet physically motivated simulation of realistic Lyman-α emitters at z ≃ 2-3, designed for ongoing and forthcoming cosmological surveys. We combine an empirical UniverseMachine galaxy-halo model with a simple spherical expanding-shell model for Lyman-α radiative transfer, calibrating only three free parameters to reproduce both the observed Lyman-α luminosity function and angular clustering. The model is further supported by its consistency with observables including the Lyman-α equivalent-width distribution, escape fraction as a function of stellar mass and dust reddening, and systemic velocity offsets. It predicts halo occupation distributions for Lyman-α emitters, the relationship between Lyα luminosity and halo mass, and the distribution of satellite emitters. This work provides a first step toward creating a high-fidelity synthetic catalog for Lyman-α cosmology surveys. The emitter catalog and spectra are publicly available with the publication.