Long Dark Gaps in the Ly$\beta$ Forest at $z<6$: Evidence of Ultra Late Reionization from XQR-30 Spectra

Yongda Zhu, George D. Becker, Sarah E. I. Bosman +22

We present a new investigation of the intergalactic medium (IGM) near reionization using dark gaps in the Lyman-$\beta$ (Ly$\beta$) forest. With its lower optical depth, Ly$\beta$ offers a pot…