The THESAN-ZOOM project: the delayed rise of Lyman continuum escape fractions in bursty high-redshift galaxies
Abstract
The ionizing radiation that galaxies release into their surroundings depends on whether efficient Lyman continuum (LyC) escape coincides with strong photon production. Stellar feedback can open escape paths as the source population fades, linking the escaping radiation to a galaxy's recent history. We investigate this timing in thirteen high-redshift (z > 3) target haloes from the THESAN-ZOOM radiation-hydrodynamic simulations, post-processed with COLT radiative transfer and sampled at ~10 Myr intervals. The clearest delayed relationship links SFR10/SFR100 to the LyC escape fraction. Selecting the nearest positive cross-correlation peak gives typical lags of ~16 Myr and peak correlations of 0.4-0.6 in massive haloes, with longer and less coherent delays towards lower masses. The fitted delays scale approximately as M⋆−0.19 and Mhalo−0.27, although the shortest lags approach the native snapshot spacing. Recurrent variations span multiple amplitude-dependent timescales, consistent with repeated episodes of star formation and feedback. Recent star formation closely tracks both intrinsic and escaping photon rates, while the escape fraction reflects the evolving gas transparency. The Hα-to-UV luminosity ratio retains a delayed association with escape, offering an observable connection between burst phase and leakage. High transparency during a fading phase can nevertheless yield little escaping radiation. The temporal overlap of photon production and transmission therefore shapes both the amount and timing of escaping radiation, informing the interpretation of observed leakers and their contribution to cosmic reionization.
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BibTeX
@misc{mehrotra2026thesanzoom,
title = {{The THESAN-ZOOM project: the delayed rise of Lyman continuum escape fractions in bursty high-redshift galaxies}},
author = {Parth Mehrotra and Aaron Smith and Yuan Bian and William McClymont and Ewald Puchwein and Rahul Kannan and Laura Keating and Xuejian Shen and Mark Vogelsberger and Sandro Tacchella and Matthew Hayes and Crystal L. Martin and Cody Carr and Anand Utsav Kapoor and Shyam Menon and Alaina Henry},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30265},
eprint = {2610.30265},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30265},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The THESAN-ZOOM project: the delayed rise of Lyman continuum escape fractions in bursty high-redshift galaxies
AU - Parth Mehrotra
AU - Aaron Smith
AU - Yuan Bian
AU - William McClymont
AU - Ewald Puchwein
AU - Rahul Kannan
AU - Laura Keating
AU - Xuejian Shen
AU - Mark Vogelsberger
AU - Sandro Tacchella
AU - Matthew Hayes
AU - Crystal L. Martin
AU - Cody Carr
AU - Anand Utsav Kapoor
AU - Shyam Menon
AU - Alaina Henry
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.30265
UR - https://arxiv.org/abs/2610.30265
AB - The ionizing radiation that galaxies release into their surroundings depends on whether efficient Lyman continuum (LyC) escape coincides with strong photon production. Stellar feedback can open escape paths as the source population fades, linking the escaping radiation to a galaxy's recent history. We investigate this timing in thirteen high-redshift (z > 3) target haloes from the THESAN-ZOOM radiation-hydrodynamic simulations, post-processed with COLT radiative transfer and sampled at ~10 Myr intervals. The clearest delayed relationship links SFR_10/SFR_100 to the LyC escape fraction. Selecting the nearest positive cross-correlation peak gives typical lags of ~16 Myr and peak correlations of 0.4-0.6 in massive haloes, with longer and less coherent delays towards lower masses. The fitted delays scale approximately as M_⋆^−0.19 and M_halo^−0.27, although the shortest lags approach the native snapshot spacing. Recurrent variations span multiple amplitude-dependent timescales, consistent with repeated episodes of star formation and feedback. Recent star formation closely tracks both intrinsic and escaping photon rates, while the escape fraction reflects the evolving gas transparency. The Hα-to-UV luminosity ratio retains a delayed association with escape, offering an observable connection between burst phase and leakage. High transparency during a fading phase can nevertheless yield little escaping radiation. The temporal overlap of photon production and transmission therefore shapes both the amount and timing of escaping radiation, informing the interpretation of observed leakers and their contribution to cosmic reionization.
ER -