Spectroscopic Ultraluminous Lyα Luminosity Functions at z = 5.7 and z = 6.6 from HEROES: Evidence for Ionized Bubbles

We present spectroscopic Ly α luminosity functions (LFs) at z = 5.7 and z = 6.6 based on a large 209 source sample of Ly α emitter (LAE) candidates identified in Subaru/Hyper Suprime-Cam narrowband imaging and confirmed with Keck II/DEIMOS spectroscopy over a multiyear observing campaign. After appl...

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Bibliographic Details
Main Authors: A. J. Taylor, A. J. Barger, L. L. Cowie, E. M. Hu, A. Songaila
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ade4c7
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Summary:We present spectroscopic Ly α luminosity functions (LFs) at z = 5.7 and z = 6.6 based on a large 209 source sample of Ly α emitter (LAE) candidates identified in Subaru/Hyper Suprime-Cam narrowband imaging and confirmed with Keck II/DEIMOS spectroscopy over a multiyear observing campaign. After applying photometric and spectroscopic cuts to produce homogeneous samples, we use the resulting samples of 49 z = 5.7 and 56 z = 6.6 LAEs to compute spectroscopic LAE LFs at each redshift. We correct our LFs for incompleteness using a source-injection simulation. We find excellent agreement with current spectroscopic and photometric LAE LFs from the literature. We look for evolution over the redshift range z = 5.7–6.6. We find a strong convergence of the LFs at L _Lyα  ≳ 10 ^43.4 erg s ^−1 . This convergence (noted in previous literature) provides strong evidence that the most luminous LAEs at z = 6.6 form ionized bubbles around themselves, allowing for greater Ly α transmission through the neutral intergalactic medium, which is measured as an increase in the bright end of the z = 6.6 LF over the expected evolution in the LF based on the faint end. We infer that ultraluminous LAEs may play a significant role in reionization.
ISSN:1538-4357