# Astrophysics - Cosmology and Nongalactic Astrophysics

## The physical origins and dominant emission mechanisms of Lyman-alpha halos: results from TNG50 in comparison to MUSE observations

Extended Lyman-alpha emission around galaxies and quasars at high redshift -- Lyman-alpha halos (LAHs) -- are now commonly detected through stacking as well as surrounding individual galaxies. Despite the increasing samples and the extensive …

## Variations of Observed Lyman-α Spectra Shapes due to the Intergalactic Absorption

Lyman-$\alpha$ (Ly$\alpha$) spectra provide insights into the small-scale structure and kinematics of neutral hydrogen (HI) within galaxies as well as the ionization state of the intergalactic medium (IGM). The former defines the intrinsic spectrum …