High-resolution numerical simulations including feedback and aimed at calculating the escape fraction (fesc) of hydrogen-ionizing photons often assume stellar radiation based on single-stellar population synthesis models. However, strong evidence suggests the binary fraction of massive stars is 70%. Moreover, simulations so far yield values of fesc falling only on the lower end of the roughly 10-20% range, the amount presumed necessary to reionize the Universe. Analyzing a high-resolution (4 pc) cosmological radiation hydrodynamic simulation we study how fesc changes when we include two different products of binary stellar evolution - stars stripped of their hydrogen envelopes and massive blue stragglers. Both produce significant amounts of ionizing photons 10-200 Myr after each starburst. We find the relative importance of these photons are amplified with respect to escaped ionizing photons, because peaks in star formation rates (SFRs) and fesc are often out of phase by this 10-200 Myr. Additionally, low mass, bursty galaxies emit Lyman continuum radiation primarily from binary products when SFRs are low. Observations of these galaxies by the James Webb Space Telescope could provide crucial information on the evolution of binary stars as a function of redshift. Overall, including stripped stars and massive blue stragglers increases our photon-weighted mean escape fraction by around 13% and 10%, respectively, resulting in a mean fesc of 17%. Our results emphasize that using updated stellar population synthesis models with binary stellar evolution provides a more sound physical basis for stellar reionization.

中文翻译：

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来自二元进化的延迟光子有助于宇宙再电离

包括反馈在内的高分辨率数值模拟旨在计算氢电离光子的逃逸分数 (fesc)，通常假设基于单恒星群合成模型的恒星辐射。然而，强有力的证据表明大质量恒星的双星比例为 70%。此外，迄今为止的模拟产生的 fesc 值仅落在大约 10-20% 范围的下限，这是重新电离宇宙所需的数量。通过分析高分辨率 (4 pc) 宇宙学辐射流体动力学模拟，我们研究了当我们包括两种不同的双星演化产物时，fesc 是如何变化的——被剥离氢包层的恒星和巨大的蓝色落后者。两者在每次星暴后都会产生大量的电离光子 10-200 Myr。我们发现这些光子的相对重要性相对于逃逸的电离光子被放大，因为恒星形成率 (SFR) 和 fesc 的峰值通常在 10-200 Myr 处异相。此外，当恒星形成率低时，低质量、爆发性星系主要从二元产物发射莱曼连续谱辐射。詹姆斯韦伯太空望远镜对这些星系的观测可以提供关于双星演化作为红移函数的重要信息。总体而言，包括剥离的恒星和巨大的蓝色落后者，我们的光子加权平均逃逸率分别增加了约 13% 和 10%，导致平均 fesc 为 17%。我们的结果强调，使用更新的恒星群合成模型和双星演化为恒星再电离提供了更可靠的物理基础。