At peak, long-duration gamma-ray bursts are the most luminous sources of electromagnetic radiation known. Since their progenitors are massive stars, they provide a tracer of star formation and star-forming galaxies over the whole of cosmic history. Their bright power-law afterglows provide ideal backlights for absorption studies of the interstellar and intergalactic medium back to the reionization era. The proposed THESEUS mission is designed to detect large samples of GRBs at z > 6 in the 2030s, at a time when supporting observations with major next generation facilities will be possible, thus enabling a range of transformative science. THESEUS will allow us to explore the faint end of the luminosity function of galaxies and the star formation rate density to high redshifts; constrain the progress of re-ionisation beyond \(z\gtrsim 6\); study in detail early chemical enrichment from stellar explosions, including signatures of Population III stars; and potentially characterize the dark energy equation of state at the highest redshifts.

在峰值时，长时间的伽马射线暴是已知的最明亮的电磁辐射源。由于它们的前身是大质量恒星，它们提供了整个宇宙历史中恒星形成和恒星形成星系的示踪剂。它们明亮的幂律余辉为星际和星际介质的吸收研究提供了理想的背光源，可以追溯到再电离时代。拟议的 THESEUS 任务旨在探测z处的大量 GRB 样本> 6 到 2030 年代，届时将有可能使用主要的下一代设施支持观测，从而实现一系列变革性科学。THESEUS 将使我们能够探索星系光度函数的微弱末端和恒星形成率密度到高红移；限制再电离的进程超过\(z\gtrsim 6\)；详细研究恒星爆炸的早期化学富集，包括星族 III 恒星的特征；并可能表征最高红移处的暗能量状态方程。