Simulating realistic Lyman-$\alpha$ emitting galaxies including the effect of radiative transfer

TL;DR

This paper develops a physically motivated simulation of Lyman-$\alpha$ emitters at redshifts 2-3, combining galaxy-halo models with radiative transfer to match observed properties and support future cosmological surveys.

Contribution

It introduces a new empirical model integrating galaxy-halo relations with radiative transfer, calibrated to reproduce multiple observed LAE properties at $z\sim2-3$.

Findings

Reproduces observed Lyman-$\alpha$ luminosity function and clustering.

Consistent with Lyman-$\alpha$ equivalent width and escape fraction data.

Provides predictions for halo occupation and satellite distributions.

Abstract

We present an empirical yet physically motivated simulation of realistic Lyman-$\alpha$ emitters (LAEs) at $z\sim2-3$, crucial for ongoing and forthcoming cosmological LAE surveys. We combine an empirical $\mathtt{UniverseMachine}$ galaxy-halo model with a simple spherical expanding shell model for the Lyman-$\alpha$ radiative transfer, calibrating only three free parameters to simultaneously reproduce the observed Lyman-$\alpha$ luminosity function and the angular clustering. Our LAE model is further supported by its consistency with other observables such as the Lyman-$\alpha$ equivalent width distribution, the Lyman-$\alpha$ escape fraction as a function of stellar mass and dust reddening, and the systemic velocity offsets. Our LAE model provides predictions for the halo occupation distributions for LAEs and relationship between Ly$\alpha$ luminosity and halo mass, including the distribution of satellite LAEs. Our work provides a crucial first step towards creating a high-fidelity LAE synthetic catalog for the LAE cosmology surveys. We make our LAE catalog and spectra publicly available upon publication.