Subaru meets JWST: A Direct Measurement of Lyα Escape Fraction at z≃6.2 with Dual Narrow-Band Imaging

@misc{shimizu2026subaru,
  title = {{Subaru meets JWST: A Direct Measurement of Ly$\boldsymbolα$ Escape Fraction at $\boldsymbolz\simeq6.2$ with Dual Narrow-Band Imaging}},
  author = {Shunta Shimizu and Nobunari Kashikawa and Ryo Emori and Junya Arita and Kohei Inayoshi and Akio K. Inoue and Kei Ito and Satoshi Kikuta and Kentaro Koretomo and Mariko Kubo and Yongming Liang and Rieko Momose and Kentaro Nagamine and Masafusa Onoue and Rhythm Shimakawa and Yoshihiro Takeda and Hisakazu Uchiyama and Takehiro Yoshioka},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2607.08264},
  eprint = {2607.08264},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2607.08264},
}

TY  - UNPB
TI  - Subaru meets JWST: A Direct Measurement of Lyα Escape Fraction at z≃6.2 with Dual Narrow-Band Imaging
AU  - Shunta Shimizu
AU  - Nobunari Kashikawa
AU  - Ryo Emori
AU  - Junya Arita
AU  - Kohei Inayoshi
AU  - Akio K. Inoue
AU  - Kei Ito
AU  - Satoshi Kikuta
AU  - Kentaro Koretomo
AU  - Mariko Kubo
AU  - Yongming Liang
AU  - Rieko Momose
AU  - Kentaro Nagamine
AU  - Masafusa Onoue
AU  - Rhythm Shimakawa
AU  - Yoshihiro Takeda
AU  - Hisakazu Uchiyama
AU  - Takehiro Yoshioka
PY  - 2026
DA  - 2026/10/30
PB  - arXiv
DO  - 10.48550/arxiv.2607.08264
UR  - https://arxiv.org/abs/2607.08264
AB  - We present a direct measurement of the Lyα escape fraction, f^Lyα_esc, for Hα emitters (HAEs) at z≃6.2 in the JWST CEERS field by combining JWST/NIRCam F470N imaging with Subaru/HSC NB872 imaging. This unique pair of narrow-band filters enables the simultaneous measurement of Hα and Lyα fluxes from galaxies during the epoch of reionization (EoR). We select 84 HAEs from F470N excesses, among which 56 have reliable NB872 photometry and 14 are detected in Lyα. The completeness-weighted stack of the HAE sample yields a median f^Lyα_esc at z≃6.2 of 0.106^+0.066_−0.044, which is in good agreement with recent measurements at similar redshifts. We further find that the stacked f_esc^Lyα shows no statistically significant change as the Hα luminosity threshold is lowered over the range probed by our sample. If Lyα escape traces Lyman continuum leakage, this may suggest that relatively Hα-luminous HAEs, rather than only the faintest ones, can provide an important contribution to the ionizing photon budget during the EoR. For individual galaxies, f^Lyα_esc positively correlates with Lyα equivalent width and negatively correlates with the UV continuum slope β. We also find a tentative trend toward higher f^Lyα_esc at smaller rest-frame UV sizes, but no significant correlation with SED-derived E(B−V) or rest-frame optical size. Although based on a limited sample, these results suggest that the galaxy-to-galaxy variation in f_esc^Lyα may be more closely linked to compact, low-attenuation star-forming components traced by the UV continuum than to global dust attenuation or the overall stellar structure.
ER  -