Next-generation telescopes such as the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (NGRST) will enable us to study the first billion years of our Universe in unprecedented detail. In this work, we use the astraeus (semi-numerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS) framework, which couples galaxy formation and reionization (for a wide range of reionization feedback models), to estimate the cosmic variance expected in the UV Luminosity Function (UV LF) and the stellar mass function in JWST surveys. We find that different reionization scenarios play a minor role in the cosmic variance. Most of the cosmic variance is completely driven by the underlying density field and increases above $100{{\ \rm per\ cent}}$ for ${\it M}_{\rm UV}\sim -17.5 ~ (-20)$ at z = 12 (6) for the JADES-deep survey (the deep JWST Advanced Extragalactic Survey with an area of 46 arcmin2); the cosmic variance decreases with an increasing survey area roughly independently of redshift. We find that the faint-end (${\it M}_{\rm UV}\gtrsim -17$) slope of the Lyman Break Galaxies (LBGs) UV LF becomes increasingly shallower with increasing reionization feedback and show how JWST observations will be able to distinguish between different models of reionization feedback at z > 9, even accounting for cosmic variance. We also show the environments (in terms of density and ionization fields) of LBGs during the EoR, finding that the underlying overdensity and ionization fraction scale positively with the UV luminosity. Finally, we also provide a public software tool to allow interested readers to compute cosmic variance for different redshifts and survey areas.

中文翻译：

---

阿斯特里乌斯——II。量化再电离时期宇宙变化的影响

下一代望远镜，如詹姆斯韦伯太空望远镜 (JWST) 和南希格雷斯罗马太空望远镜 (NGRST)，将使我们能够以前所未有的细节研究宇宙的最初十亿年。在这项工作中，我们使用 astraeus（N 体暗物质模拟中星系形成和再电离的半数值辐射传递耦合）框架，该框架将星系形成和再电离耦合（适用于广泛的再电离反馈模型），以估计紫外光度函数 (UV LF) 和 JWST 调查中的恒星质量函数中预期的宇宙方差。我们发现不同的再电离场景在宇宙方差中起次要作用。大多数宇宙方差完全由潜在的密度场驱动，并且对于 ${\it M}_{\rm UV}\sim -17 增加到 $100{{\ \rm per\ cent}}$ 以上。5 ~ (-20)$ at z = 12 (6) 用于 JADES 深度测量（深度 JWST 高级河外测量，面积为 46 arcmin2）；宇宙方差随着调查区域的增加而减小，大致独立于红移。我们发现莱曼断裂星系 (LBGs) UV LF 的微弱端 (${\it M}_{\rm UV}\gtrsim -17$) 斜率随着再电离反馈的增加而变得越来越浅，并展示了 JWST 观测将如何能够在 z > 时区分不同的再电离反馈模型；9，甚至考虑到宇宙方差。我们还展示了 EoR 期间 LBG 的环境（就密度和电离场而言），发现潜在的过密度和电离分数与紫外光度呈正相关。最后，