The Lyman-alpha cosmic web in TNG50

Abstract

The cosmic web can potentially be observed in direct emission through the Lyman-alpha line. While luminous Lyman-alpha emitters are already an established powerful tracer of the matter distribution in the high-redshift universe, the implications of the faint Lyman-alpha glow within the cosmic web (away from luminous emitters) remains to be explored. In this talk, I will characterize the Lyman-alpha cosmic web using radiative transfer simulations on top of the cosmological magnetohydrodynamical galaxy formation simulation suite IllustrisTNG across different spatial scales and evaluate the feasibility for the Lyman-alpha cosmic web’s future detection. I show the complex trajectories taken by Lyman-alpha photons on their way towards an observer, along with a discussion of the origins of these largest Lyman-alpha structures in emission, their underlying halo population, and commonly traced gas properties.