S18A0107abst
S18A0107
We propose FOCAS spectroscopy for bright Lyα Emitter (LAE) candidates at z≃5.7−6.6 identified with ≃21 deg2 narrowband (NB) data of the Hyper Suprime-Cam (HSC) survey. Thanks to the large area HSC NB data, we identify 6 very rare and bright LAE candidates with a Lyα luminosity of logLLyα/erg s−1>sim43.7. These bright LAE candidates are sources of the significant LAE number density excess over the Schechter-form Lyα luminosity functions (LFs), so-called the bright-end excess. We will carry out spectroscopic follow-up observations for the 6 bright LAE candidates through Lyα detections. Based on the flux of N v line covered by the FOCAS spectra, we also examine the presence of active galactic nucleus (AGN) activity in the bright LAEs. Exploiting the spectroscopic data of bright HSC LAEs obtained in this program and our previous observations, we understand the physical origins of the bright-end excess in Lyα LFs: due to the AGN activity, large ionized bubbles surrounding bright LAEs, or contaminations of low-z emitters to the LAE sample? In addition, we will obtain the number density of faint AGNs in bright LAEs at z≃5.7−6.6, and constrain the ionizing photon contributions of faint AGNs responsible for the cosmic reionization.
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