发表机构
Cosmic Dawn Center (DAWN)（宇宙黎明中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
Shark半解析模型无需修改重子物理，通过剧烈盘不稳定性触发星暴的机制，自然重现了z>10的明亮紫外星系及相关观测约束。
AI 中文摘要
詹姆斯·韦布空间望远镜（JWST）揭示了众多z>10的明亮紫外（UV）星系的存在，这可能挑战Λ冷暗物质（ΛCDM）宇宙中的星系形成模型。已有研究提出修改恒星形成和恒星反馈模型来缓解这种张力，但根本挑战在于设计一个能同时重现从z=0到最高红移观测结果的星系形成模型。本文呈现了经调整以重现z=0宇宙的Shark星系形成半解析模型的预测结果。研究表明，该模型无需改变重子物理模型，即可重现直至z=17的当前紫外光度函数约束条件；在0<z<15的范围内，该模型也能合理重现从z=0到z=10的恒星质量函数演化及宇宙恒星形成率（SFR）密度，且采用相同的重子物理和参数。Shark模型成功的关键在于其包含的由剧烈盘不稳定性触发的星暴机制，该机制导致z>10时紫外光度随晕质量的方差增大。研究证实，若缺少该机制，模型中的星系将缺乏足够的星暴活动，无法重现z>10的观测结果。
英文摘要
The James Webb Space Telescope (JWST) has unveiled the existence of numerous z>10 bright ultraviolet (UV) galaxies, potentially challenging galaxy formation models in a Lambda Cold Dark Matter (LCDM) universe. Modifications to star formation and stellar feedback models have been suggested to alleviate the tension. However, the fundamental challenge is to design a galaxy formation model that simultaneously reproduces observations from z=0 to those at the highest redshifts. Here, we present predictions from the Shark semi-analytic model of galaxy formation, which is tuned to reproduce the z=0 universe. We show that the same model is capable of reproducing the current UV luminosity function constraints even up to z=17 without the need to invoke variations in the baryon physics model. This model is also capable of reproducing reasonably well the stellar mass function evolution from z=0 to z=10 and the cosmic star formation rate (SFR) density at 0<z<15, again with the same baryon physics and parameters. The key to the success of Shark is the triggering of starbursts by violent disk instabilities included in the model, which leads to an increase in the variance of the UV luminosity with increasing halo mass at z>10. We demonstrate that without this mechanism, galaxies are not bursty enough in the model to reproduce the observations at z>10.
Comments20 pages, 9 figures. Submitted to MNRAS. Comments welcome!
