AI 中文总结
本研究扩展SCRIPT框架以计算宇宙黎明的21厘米自旋温度涨落，发现全局21厘米信号存在简并性，但21厘米功率谱可区分红移演化与静态星系群体，需结合两类测量约束高红移星系演化。
AI 中文摘要
詹姆斯·韦布空间望远镜（JWST）的最新观测显示，在红移z≳10处发光星系的丰度意外偏高，这对传统恒星形成模型构成了挑战。中性氢的21厘米信号为这些早期时代提供了互补的体积平均探测手段。本研究对显式光子守恒的半数值框架SCRIPT进行了重大扩展，使其能够自洽计算由宇宙黎明期间非均匀莱曼-α耦合和X射线加热驱动的自旋温度涨落。利用该框架，我们对比了基于JWST观测的基准星系模型（具有红移演化的恒星形成效率）与静态基线模型。研究表明，全局21厘米信号存在高度简并性：若采用陡峭的、与质量相关的X射线效率，将星系际介质加热转向丰度极高的低质量暗晕，静态星系群体可复制演化群体的吸收谷。但21厘米功率谱可明确打破该简并性：由于空间涨落保留了源暗晕成团偏差的结构记忆，经调整的静态模型在所有特征峰上预测的功率谱振幅显著更低。我们得出结论，结合全局测量与涨落测量对可靠约束高红移星系的红移演化至关重要。
英文摘要
Recent James Webb Space Telescope (JWST) observations suggest an unexpectedly high abundance of luminous galaxies at $z \gtrsim 10$, challenging traditional models of star formation. The 21-cm signal of neutral hydrogen offers a complementary, volume-averaged probe of these early epochs. In this work, we present a major extension to the explicitly photon-conserving semi-numerical framework SCRIPT, enabling the self-consistent calculation of spin temperature fluctuations driven by inhomogeneous Lyman-$α$ coupling and X-ray heating during the Cosmic Dawn. Using this framework, we compare a JWST-informed fiducial galaxy model, featuring a redshift-evolving star-formation efficiency, against a static baseline model. We demonstrate that the global 21-cm signal is highly degenerate: a static galaxy population can replicate the absorption trough of an evolving population if a steep, mass-dependent X-ray efficiency is invoked to shift intergalactic medium heating toward highly abundant, low-mass halos. However, this degeneracy is definitively broken by the 21-cm power spectrum. Because spatial fluctuations retain a structural memory of the clustering bias of the source halos, the tuned static model predicts a substantially lower power spectrum amplitude across all characteristic peaks. We conclude that combining global and fluctuation measurements is essential to robustly constrain the redshift evolution of high-redshift galaxies.
Comments26 pages, 4 figures, 1 table. To be submitted to JCAP
