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Abstract We present two uniformly observed spectroscopic samples of Lyαemitters (LAEs; 127 atz= 5.7 and 82 atz= 6.6), which we use to investigate the evolution of the LAE population at these redshifts. The observations cover a large field (44 deg²) in the North Ecliptic Pole, as well as several smaller fields. We have a small number of exotic LAEs in the samples: double-peaked Lyαprofiles; very extended red wings; and one impressive lensed LAE cross. We also find three broad-line active galactic nuclei. We compare the Lyαline width measurements at the two redshifts, finding that the lower-luminosity LAEs show a strong evolution of decreasing line width with increasing redshift, while the high-luminosity LAEs do not, with a transition luminosity of logL(Lyα) ≈ 43.25 erg s⁻¹. Thus, atz= 6.6, the high-luminosity LAEs may be producing large ionized bubbles themselves, or they may be residing in overdense galaxy sites that are producing such bubbles. In order to avoid losses in the red wing, the radius of the ionized bubble must be larger than 1 pMpc. The double-peaked LAEs also require transmission on the blue side. For the four atz= 6.6, we use models to estimate the proximity radii,R_a, where the ionizing flux of the galaxy is sufficient to make the surroundings have a low enough neutral fraction to pass the blue light. Since the requiredR_aare large, multiple ionizing sources in the vicinity may be needed. 

Abstract We present a seven-band (g,r,i,z,y, NB816, NB921) catalog derived from a Subaru Hyper Suprime-Cam (HSC) imaging survey of the North Ecliptic Pole (NEP). The survey, known as HEROES, consists of 44 deg²of contiguous imaging reaching median 5σdepths ofg: 26.5,r: 26.2,i: 25.7,z: 25.1,y: 23.9, NB816: 24.4, and NB921: 24.4 mag. We reduced these data with the HSC pipeline softwarehscPipe, and produced a resulting multiband catalog containing over 25 million objects. We provide the catalog in three formats: (1) a collection ofhscPipeformat forced photometry catalogs, (2) a single combined catalog containing every object in that data set with selected useful columns, and (3) a smaller variation of the combined catalog with only essential columns for basic analysis or low-memory machines. The catalog uses all the available HSC data on the NEP and may serve as the primary optical catalog for current and future NEP deep fields from instruments and observatories such as SCUBA-2, eROSITA, Spitzer, Euclid, and JWST. 

Abstract Recent evidence suggests that high-redshift Ly α emitting galaxies (LAEs) with log L ( Ly α ) > 43.5 erg s − 1 , referred to as ultraluminous LAEs (ULLAEs), may show less evolution than lower-luminosity LAEs in the redshift range z = 5.7–6.6. Here we explore the redshift evolution of the velocity widths of the Ly α emission lines in LAEs over this redshift interval. We use new wide-field, narrowband observations from Subaru/Hyper Suprime-Cam to provide a sample of 24 z = 6.6 and 12 z = 5.7 LAEs with log L ( Ly α ) > 43 erg s − 1 , all of which have follow-up spectroscopy from Keck/DEIMOS. Combining with archival lower-luminosity data, we find a significant narrowing of the Ly α lines in LAEs at log L ( Ly α ) < 43.25 erg s − 1 —somewhat lower than the usual ULLAE definition—at z = 6.6 relative to those at z = 5.7, but we do not see this in higher-luminosity LAEs. As we move to higher redshifts, the increasing neutrality of the intergalactic medium should increase the scattering of the Ly α lines, making them narrower. The absence of this effect in the higher-luminosity LAEs suggests they may lie in more highly ionized regions, self-shielding from the scattering effects of the intergalactic medium.