The faint Lyman-alpha cosmic web in TNG50

Abstract

The diffuse filaments of the cosmic web can potentially be observed in 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) remain to be explored. Combining cosmological magnetohydrodynamical galaxy formation simulations (TNG50) with explicit calculation of the Lyman-alpha radiative transfer, I will discuss the nature of large-scale, diffuse Lyman-alpha filaments and their detectability with recent IFU instruments, including MUSE, KCWI, and VIRUS.