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arXiv 2602.02658astro-ph.GAastro-ph.CO
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宇宙CO和[CII]背景及12 Gyr内恒星形成燃料的供给

Cosmic CO and [CII] backgrounds and the fueling of star formation over 12 Gyr

Academia Sinica Institute of Astronomy and Astrophysics(中央研究院天文及天文物理研究所)

Yi-Kuan Chiang

AI总结:

研究通过检测宇宙CO和[CII]背景,揭示了恒星形成燃料的全球分布及分子气体储量对银河系增长的影响。

摘要:

分子气体在质量上虽不显突出,但在宇宙库存中却至关重要,作为恒星形成直接的燃料调节着重子循环。在大部分宇宙历史中,其储量一直难以捉摸,只有通过明亮的碳monoxide(CO)发射星系才揭示出冰山一角。本文报告了首次在7σ置信度下检测到宇宙平均CO背景,其在旋转跃迁级上跨越0<z<4.2范围,同时检测到离子化碳([CII])在3σ置信度下。这利用了对稀疏宽带强度的体积成像与参考星系的聚类分析,直接探测了宇宙网中的整体发射。通过CO(1-0)我们推断出总分子气体密度,Ω_H2,发现其约为银河系调查中解析出的两倍。全球耗尽时间约为1 Gyr,比哈勃时间短,要求持续的流入。CO激发与恒星形成表面积密度相关,并与耗尽时间一起,产生了一种超线性的肯尼特-施密特定律,似乎具有普遍性。这些结果共同确立了由更大、寿命较短的分子储备驱动的银河系增长的全球图景。CO和[CII]的检测标志着线强度测绘的转折点,用实证线强度取代预测,并定义了即将到来的3D实验的灵敏度要求,这些实验将打开新的银河系形成和宇宙学研究窗口。

英文摘要:

Molecular gas, modest in mass yet pivotal within the cosmic inventory, regulates baryon cycling as the immediate fuel for star formation. Across most of cosmic history, its reservoir has remained elusive, with only the tip of the iceberg revealed by luminous carbon monoxide (CO) emitting galaxies. Here we report the first detections of the mean cosmic CO background across its rotational ladder at 7$σ$, together with ionized carbon ([CII]) at 3$σ$, over $0<z<4.2$. This uses tomographic clustering of diffuse broadband intensities with reference galaxies, directly probing aggregate emission in the cosmic web. From CO(1-0) we infer the total molecular gas density, $Ω_{\rm H_2}$, finding it about twice that resolved in galaxy surveys. The global depletion time is $\sim$1 Gyr, shorter than the Hubble time, requiring sustained inflow. CO excitation links to star-formation surface density and, with depletion time, yields a super-linear Kennicutt-Schmidt law that appears universal. Together these results establish a global picture of galaxy growth fueled by a larger, short-lived molecular reservoir. The CO and [CII] detections mark a turning point for line-intensity mapping, replacing forecasts with empirical line strengths and defining sensitivity requirements for upcoming 3D experiments poised to open new windows on galaxy formation and cosmology.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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