Insight from JWST/NIRCam into galaxy overdensities around bright Ly$\alpha$ emitters during reionization: implications for ionized bubbles at $z \sim 9$

Understand

Several studies have detected Lyman-alpha (Ly$\alpha$) from bright ($M_\mathrm{UV}\lesssim-21.5$) galaxies during the early stages of reionization despite the significantly neutral intergalactic medium.

• To explain these detections, it has been suggested that $z>7$ Ly$\alpha$ emitters (LAEs) inhabit physical Mpc (pMpc)-scale ionized regions powered by overdensities of faint galaxies, but systematic searches for these overdensities near LAEs have been challenging.
• Here, we use CEERS JWST/NIRCam imaging to search for large-scale galaxy overdensities near two very UV-bright, $z=8.7$ LAEs in the EGS field.
• We colour select 27 $z=8.4-9.1$ candidates, including the one LAE in the footprint (EGSY8p7).