Kavli Affiliate: Naoshi Sugiyama | Summary:Neutral hydrogen (H$_rm I$) intensity mapping is capable of measuring redshift evolution of H$_rm I$ density parameter $Ω_rm H_rm I$, which is an important parameter to understand structure formation in the post-reionization epoch. Future H$_rm I$ observation with Square Kilometre Array (SKA) can significantly improve constraints on the parameter. However, […]