2025ApJ...995L..31S

We report on the statistical analysis of quasar photoevaporation at z ∼ 2.2 by comparing the density of surrounding Lyα emitters (LAEs) and continuum-selected galaxies, based on the imaging data of the Hyper Suprime-Cam (HSC) Subaru Strategic Program and the CFHT Large Area U-band Deep Survey. We select 18 quasars from the Sloan Digital Sky Survey in the HSC Deep/UltraDeep fields, normalize the LAE/continuum-selected galaxy distribution around each quasar with the quasar proximity size, stack them, and then measure the average densities of the galaxies. As a result, we find that the density of LAEs is ≳5σ lower than that of continuum-selected galaxies within the quasar proximity region. Within the quasar proximity region, we find that the LAEs with high Lyα equivalent widths (EWs) are less dense than those with low EWs at the 3σ level and that LAEs with EW of ≳150 Å (rest-frame) are predominantly scarce. Finally, we find that both LAEs and continuum-selected galaxies have smaller densities when they are closer to quasars. We argue that the photoevaporation effect is more effective for smaller dark matter halos predominantly hosting LAEs, but that it may also affect larger halos.