The Evolution of the Ultraluminous Lyman-alpha Luminosity Function from z=6.6 to z=5.7

We present the luminosity functions (LFs) for ultraluminous Lyman-alpha emitting galaxies (LAEs) at z=5.7 and z=6.6, defining ultraluminous LAEs (ULLAEs) as galaxies with log L (Lya)>43.5 erg/s. These galaxies make up the very bright end of the Lyα LF and provide insight into leading theories about the formation of ionized bubbles around luminous galaxies that may have been primary drivers of reionization. Using a 30 sq. degree Subaru Hyper Suprime-Cam survey centered on the North Ecliptic Pole with both broadband (grizy) and narrowband (NB816 and NB921) components, we selected candidates based on color cuts (g',r',i'>26, NB921<23.5, and z'-NB921>1.3 at z=6.6), (g',r'>26, NB816<23.5, i'-NB816>1.3, and z'-NB816>1.0 at z=5.7) and visual inspections. We followed up 14 candidates spectroscopically with DEIMOS on Keck II, confirming 9 candidates as ULLAEs at z=6.6. We recently observed 17 candidates at z=5.7 with DEIMOS and confirming 12 as z=5.7 LAEs (9 ULLAEs). We applied a comprehensive incompleteness correction to both LFs based on simulations of over 27 million test sources. We compare our recent z=6.6 ULLAE LF to our new z=5.7 ULLAE LF in order to determine the evolution of the ultraluminous LF near the end of the epoch of reionization.