The Lyman-limit photon mean free path at the end of late reionization in the Sherwood–Relics simulations

Feron, Jennifer; Conaboy, Luke; Bolton, James S.; Chapman, Emma; Haehnelt, Martin G.; Keating, Laura C.; Kulkarni, Girish; Puchwein, Ewald

Abstract

Recent evidence supporting reionization ending at redshift z ≲ 6 includes the rapid redshift evolution of the mean free path, λmfp , for Lyman-limit photons through the intergalactic medium (IGM) at 5 < z < 6. Here, we investigate λmfp predicted by the Sherwood–Relics suite of hybrid radiation hydrodynamical simulations. Simulations with comoving volumes of 40 3 h −3 cMpc 3 (160 3 h −3 cMpc 3 ), calibrated to match the observed Ly α forest transmission with a late end to reionization at z < 6, are consistent with recent λmfp measurements at z < 5 . 9, and are 1 . 2 σ (1 . 8 σ) above the highest redshift λmfp measurement at z = 5 . 93. The majority of the Lyman-limit opacity at the end of reionization is attributable to highly ionized Ly α forest absorbers with neutral hydrogen column densities N HI ≤ 10 16 –10 17 cm −2 . Resolving these systems is critical for capturing the redshift evolution of λmfp during the final stages of reionization. After reionization completes, overdense gas will reduce λmfp by up to 20 per cent around haloes with masses M h ∼ 10 9 –10 11 h −1 M , but during reionization ionized bubbles will instead boost λmfp around haloes by up to an order of magnitude when the IGM is as much as 90 per cent neutral by volume. This effect will play an important role in the visibility of Ly α emitting galaxies at z ≳ 10 discovered with JWST .

Citation

Feron, J., Conaboy, L., Bolton, J. S., Chapman, E., Haehnelt, M. G., Keating, L. C., Kulkarni, G., & Puchwein, E. (2024). The Lyman-limit photon mean free path at the end of late reionization in the Sherwood–Relics simulations. Monthly Notices of the Royal Astronomical Society, 532(2), 2401-2417. https://doi.org/10.1093/mnras/stae1636

• Journal Article Type: Article
• Acceptance Date: Jul 1, 2024
• Online Publication Date: Jul 10, 2024
• Publication Date: 2024-08
• Deposit Date: Jul 22, 2024
• Publicly Available Date: Jul 23, 2024
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 532
• Issue: 2
• Pages: 2401-2417
• DOI: https://doi.org/10.1093/mnras/stae1636
• Keywords: methods: numerical, intergalactic medium, quasars: absorption lines, large scale structure of Universe
• Public URL: https://nottingham-repository.worktribe.com/output/37320094
• Publisher URL: https://academic.oup.com/mnras/article/532/2/2401/7710764