从恒星尘埃到首批星系中的星际尘埃增长：红移 z ~ 8.9 附近尘埃演化的宇宙学转变
From stardust to interstellar grain growth in the first galaxies: a cosmological transition in dust evolution near z ~ 8.9
- Aix Marseille Université, CNRS, CNES, LAM（艾克斯马赛大学）
- Chalmers University of Technology（查尔姆斯理工大学）
- Dipartimento di Fisica, “Sapienza” Università di Roma（罗马智慧大学物理系）
- INAF/Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）
- INFN, Sezione di Roma I（意大利国家核物理研究所罗马第一分部）
- Sapienza School for Advanced Studies（罗马智慧大学高等研究院）
- Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天文物理学研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用JWST、ALMA和NOEMA观测及变点分析，发现首批星系尘埃演化在红移z~8.9（大爆炸后约5.7亿年）发生从超新星尘埃主导到星际颗粒增长主导的宇宙学转变。
AI中文摘要：
尘埃何时以及如何开始塑造星系？受星系尘埃质量中明显红移断裂的识别（表明在 $z \gtrsim 9$ 处尘埃质量显著降低）的启发，我们研究了宇宙历史最初十亿年间的尘埃增丰过程。我们旨在确定观测到的演化是否标志着主导尘埃产生机制的转变，并识别预期发生这种转变的物理条件。利用 JWST、ALMA 和 NOEMA 的观测，我们测量了紫外尘埃消光和尘埃质量。我们应用了截尾变点分析，并将观测结果与尘埃演化模型进行了比较。分析识别出一个优选转变点，位于红移 z ~ 8.9 附近，对应大爆炸后约 5.7 亿年。断裂的证据在尘埃质量和尘埃-恒星质量比中最为强烈，这些数据主要来自 JWST NIRSpec 分光光度拟合，部分也来自亚毫米数据。紫外消光测量与同一时期的转变一致，但并不独立要求存在转变。模型与高效星际尘埃增长在特征金属丰度之上的开始相一致。我们将 z ~ 8.9 附近的转变解释为尘埃演化从早期由超新星产生的尘埃主导的机制，转变为以颗粒增长为主导的机制。第三星族星的增丰可以改变最早的化学增丰历史，但几乎不改变尘埃转变的时间，并且不是其出现所必需的。
英文摘要：
When and how did dust begin to shape galaxies? Motivated by the identification of an apparent redshift break in galaxy dust masses, suggesting substantially lower dust masses at $z \gtrsim 9$, we investigate dust enrichment during the first billion years of cosmic history. We aim to determine whether the observed evolution marks a transition in the dominant dust-production mechanism and to identify the physical conditions under which such a transition is expected to occur. Using JWST, ALMA, and NOEMA observations, we measure ultraviolet dust attenuation and dust masses. We apply a censored change-point analysis and compare the observations with dust evolution modelling. The analysis identifies a preferred transition near redshift z ~ 8.9, corresponding to about 570 Myr after the Big Bang. The evidence for a break is strongest in dust mass and dust-to-stellar mass ratio, mostly estimated from JWST NIRSpec spectrophotometric fitting but also partly from sub-mm data. The ultraviolet attenuation measurements are consistent with a transition at the same epoch but do not independently require one. The models are consistent with the onset of efficient interstellar grain growth above a characteristic metallicity. We interpret the transition near z ~ 8.9 as the emergence of grain-growth-dominated dust evolution from an earlier regime dominated by supernova-produced grains. Population III enrichment can modify the earliest chemical-enrichment history but leaves the timing of the dust transition nearly unchanged and is not required for its emergence.
