The Evolution of Ly? Emitter Line Widths from z = 5.7 to z = 6.6

Recent evidence suggests that high-redshift Ly-alpha emitting galaxies (LAEs) with logL(Ly-alpha) > 43.5 erg/s, referred to as ultraluminous LAEs (ULLAEs), may show less evolution than lower-luminosity in the redshift range z=5.7-6.6. Here we explore of velocity widths emission lines over this interval. We use new wide-field, narrowband observations from Subaru/Hyper Suprime-Cam provide a sample 24 z=6.6 and 12 z=5.7 log L(Ly-alpha) 43 all which have follow-up spectroscopy Keck/DEIMOS. Combining archival data, find significant narrowing at < 43.25 erg/s -- somewhat lower usual ULLAE definition z = 6.6 relative those 5.7, but do not see higher-luminosity LAEs. As move higher redshifts, increasing neutrality intergalactic medium should increase scattering lines, making them narrower. The absence effect they lie more highly ionized regions, self-shielding effects medium.