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

2025/06/16 by Anthony J. Taylor, A. J. Barger, Taylor, A. J. +7
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Atmospheric Ozone and Climate #Atomic and Subatomic Physics Research #FOS: Physical sciences #Ionosphere and magnetosphere dynamics

paper · pdf · doi:10.48550/arxiv.2506.13854

openalex publication_date 2025/06/16 · openalex created_date 2025/10/18 · openalex updated_date 2026/07/28

Abstract

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

Citations

• SILVERRUSH. XIV. Lya Luminosity Functions and Angular Correlation Functions from ~20,000 Lya Emitters at z~2.2-7.3 from upto 24 \rm deg² HSC-SSP and CHORUS Surveys: Linking the Post-Reionization Epoch to the Heart of Reionization
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Third data release of the Hyper Suprime-Cam Subaru Strategic Program
• The Astropy Project: Building an Open-science Project and Status of the v2.0 Core Package*
• The Hyper Suprime-Cam SSP Survey: Overview and survey design
• emcee : The MCMC Hammer

Related

• A spectroscopic survey of Lyα emitters and Lyα luminosity function at Redshifts 3.7 and 4.8
• A Spectral Atlas of Lyman Alpha Emitters at z = 5.7 and z = 6.6
• Census of Lyα Emission from ∼ 600 Galaxies at z=5-14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization
• The MAGPI Survey: Insights into the Lyman-alpha line widths and the size of ionized bubbles at the edge of cosmic reionization
• SILVERRUSH. XIII. A Catalog of 20,567 Lyα Emitters at z=2-7 Identified in the Full-depth Data of the Subaru/HSC-SSP and CHORUS Surveys