标题： 介绍Phoebos模拟：星系形成初期的星系特性 显示英文标题

标题： Introducing the Phoebos simulation: galaxy properties at the dawn of galaxy formation

摘要： 詹姆斯·韦布空间望远镜（JWST）现在使我们能够以前所未有的细节观察宇宙黎明末期（$z \sim 10-15$）的星系，揭示它们的形态、大小和内部结构。 这些观测为驱动早期星系形成的过程提供了关键见解。 在本研究中，我们介绍了Phoebos流体动力学宇宙学模拟，这是一个最先进的100 Mpc体积，旨在研究宇宙黎明末期及再电离时期星系的形成和演化。 Phoebos包含一个有意设计得较弱的恒星反馈模型，以解决JWST在早期宇宙中看到的大量大质量星系的问题。 与大多数大型宇宙流体动力学模拟不同，我们没有采用有效状态方程模型，而是我们的辐射冷却模型使我们能够捕捉星系内外气体的多相性质。 Phoebos在$z \gtrsim 8$重现了早期星系形成的关键可观测量，包括恒星质量函数和恒星质量与晕质量的关系。 它还恢复了恒星大小与质量关系的观测斜率，并与特定恒星形成率非常吻合。 这些结果表明，在仅有轻微恒星反馈调节的情况下，高效的恒星形成驱动了早期星系的增长，支持了宇宙黎明期间快速恒星质量组装的情景。 宇宙恒星形成密度有迹象表明，在较低红移时， Phoebos可能会高估系统内的恒星质量，这表明为了再现后期观测，可能需要转向更强的恒星反馈。 这些结果突显了Phoebos解释JWST观测和探索塑造星系形成的演化物理过程的潜力。 显示英文摘要

摘要： The James Webb Space Telescope (JWST) now allows us to observe galaxies at the end of cosmic dawn ($z \sim 10-15$) with unprecedented detail, revealing their morphologies, sizes, and internal structures. These observations offer crucial insights into the physical processes driving early galaxy formation. In this work, we introduce the Phoebos hydrodynamical cosmological simulation, a state-of-the-art 100 Mpc volume designed to study the formation and evolution of galaxies at the end of cosmic dawn and into the epoch of reionization. Phoebos includes a stellar feedback model that is intentionally weak, in order to address the high abundance of massive galaxies seen by JWST at early epochs. At variance with most large cosmological hydrodynamical simulations, we do not employ an effective equation of state model, instead our radiative cooling model allows us to capture the multi-phase nature of the gas inside and around galaxies. Phoebos reproduces key observables of early galaxy formation at $z \gtrsim 8$, including the stellar mass function and the stellar-to-halo mass relation. It also recovers the observed slope of the stellar size-to-mass relation and matches the specific star formation rate remarkably well. These results suggest that highly efficient star formation in the presence of only mild regulation from stellar feedback, drives early galaxy growth, supporting a scenario of rapid stellar mass assembly during cosmic dawn. There are indications in the cosmic star formation density that, at lower redshifts, Phoebos might overpredict the stellar mass within the systems, suggesting that a transition to a stronger stellar feedback may be necessary to reproduce later-time observations. These results highlight the potential of Phoebos to interpret JWST observations and to probe the evolving physical processes that shape galaxy formation.