In this work, we use the astraeus (seminumerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS) framework that couples galaxy formation and reionization in the first billion years. Exploring a number of models for reionization feedback and the escape fraction of ionizing radiation from the galactic environment (fesc), we quantify how the contribution of star-forming galaxies (with halo masses $M_\mathrm{ h}\gt 10^{8.2}\, {\rm \rm M_\odot }$) to reionization depends on the radiative feedback model, fesc, and the environmental overdensity. Our key findings are: (i) for constant fesc models, intermediate-mass galaxies (with halo masses of $M_\mathrm{ h}\simeq 10^{9-11}\, {\rm \rm M_\odot }$ and absolute UV magnitudes of MUV ∼ −15 to −20) in intermediate-density regions (with overdensity log10(1 + δ) ∼ 0−0.8 on a 2 comoving Mpc spatial scale) drive reionization; (ii) scenarios where fesc increases with decreasing halo mass shift, the galaxy population driving reionization to lower mass galaxies ($M_\mathrm{ h}\lesssim 10^{9.5}\, {\rm \rm M_\odot }$) with lower luminosities (MUV ≳ −16) and overdensities [log10(1 + δ) ∼ 0−0.5 on a 2 comoving Mpc spatial scale]; (iii) reionization imprints its topology on the ionizing emissivity of low-mass galaxies ($M_h\lesssim 10^{9}\, {\rm \rm M_\odot }$] through radiative feedback. Low-mass galaxies experience a stronger suppression of star formation by radiative feedback and show lower ionizing emissivities in overdense regions; (iv) a change in fesc with galaxy properties has the largest impact on the sources of reionization and their detectability, with the radiative feedback strength and environmental overdensity playing a sub-dominant role; (v) James Webb Space Telescope-surveys (with a limiting magnitude of MUV = −16) will be able to detect the galaxies providing ${\sim}60{-}70{{\ \rm per\ cent}}$ (${\sim}10{{\ \rm per\ cent}}$) of reionization photons at z = 7 for constant fesc models (scenarios where fesc increases with decreasing halo mass).

中文翻译：

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阿斯特里乌斯——III。再电离源的环境和物理性质

在这项工作中，我们使用了 astraeus（N 体暗物质模拟中星系形成和再电离的半数辐射转移耦合）框架，该框架在最初的十亿年中耦合了星系的形成和再电离。探索了一些用于再电离反馈和星系环境中电离辐射逃逸分数 (fesc) 的模型，我们量化了恒星形成星系的贡献（晕质量 $M_\mathrm{ h}\gt 10^{8.2 }\, {\rm \rm M_\odot }$) 到再电离取决于辐射反馈模型、fesc 和环境过密度。我们的主要发现是：(i) 对于恒定 fesc 模型，中等质量星系（晕质量为 $M_\mathrm{ h}\simeq 10^{9-11}\，{\rm \rm M_\odot }$ 和 MUV 的绝对 UV 幅度 ~ -15 到 -20) 在中等密度区域（在 2 共移动 Mpc 空间尺度上具有过密度 log10(1 + δ) ~ 0−0.8）驱动再电离；(ii) fesc 随着光晕质量转移的减少而增加的场景，星系群推动再电离到低质量星系 ($M_\mathrm{ h}\lesssim 10^{9.5}\, {\rm \rm M_\odot }$)具有较低的光度 (MUV ≳ -16) 和过密度 [log10(1 + δ) ∼ 0−0.5 on a 2 comoving Mpc 空间尺度]；(iii) 再电离通过辐射反馈将其拓扑印记在低质量星系的电离发射率 ($M_h\lesssim 10^{9}\, {\rm \rm M_\odot }$] 上。通过辐射反馈抑制恒星形成，并在高密度区域显示较低的电离发射率；(iv) fesc 随星系特性的变化对再电离源及其可探测性影响最大，辐射反馈强度和环境超密度起次要作用；(v) James Webb Space Telescope-surveys（限制星等为 MUV = -16）将能够探测到提供 ${\sim}60{-}70{{\ \rm per\ cent}}$ ( ${\sim}10{{\ \rm per\ cent}}$) 个在 z = 7 处的再电离光子，用于恒定 fesc 模型（fesc 随着晕质量减少而增加的场景）。