The physical origin for spatially large scatter of IGM opacity at the end of reionization: The IGM Ly? opacity-galaxy density relation

The large opacity fluctuations in the $z > 5.5$ Ly$\alpha$ forest may indicate inhomogeneous progress of reionization. To explain observed scatter effective optical depth ($\tau_{\rm eff}$) intergalactic medium (IGM), fluctuation UV background ($\Gamma$ model) or IGM gas temperature ($T$ have been proposed, which predict opposite correlations between $\tau_{\rm eff}$ and galaxy density. In order to address model can eff}$, we search for emitters (LAEs) around two (J1137+3549 J1602+4228) quasar sightlines with eff}\sim3$ J1630+4012 sightline eff}\sim5.5$. Using a narrowband imaging Subaru/Hyper Suprime-Cam, draw LAE density maps explore their spatial distributions. Overdensities are found within 20 $h^{-1}$Mpc low regions, while deficit LAEs is high region. Although three neither nor enough clearly distinguish models, these eff}$-galaxy relations all consistently support $\Gamma$ rather than $T$ fields, along previous studies. overdensities near suggest that relic does not affect reionization much. Otherwise, could be attributed other factors besides process, such as nature poor tracers underlying large-scale structures.