近日，加拿大不列颠哥伦比亚大学Dazhi Zhou团队报道了Sunyaev-Zeldovich探测红移4.3的星团内热气体。2026年1月5日，《自然》杂志发表了这一成果。

当今星系团中的大多数重子以热气体（?107 K）的形式存在，构成了团内介质（ICM）。宇宙学模拟预测，随着年轻星系团中的团内气体仍在聚集和加热，ICM的质量和温度会向更早的时间推移而下降。迄今为止，仅在少数几个红移（z）约等于或大于2的系统中可靠地检测到了热ICM，这使得ICM聚集的时间和机制仍不确定。

研究组报告了利用阿塔卡马大型毫米/亚毫米阵列（ALMA）通过原星系团SPT2349–56的Sunyaev–Zeldovich特征直接观测到团内热气体。在红移为4.3时，SPT2349–56在约100千秒差距的区域内拥有一个大型分子气体储层和三个射电亮活动星系核（AGN）。测量结果表明，核心区域的热能约为1061尔格，是仅由引力产生的能量的约10倍。与当前的理论预期相反，SPT2349–56中的热ICM表明，在团聚集的早期阶段就可能发生大量加热，在成熟星系团在红移约2时变得普遍之前，就已沉积了足够的能量使新生ICM过热。

附：英文原文

Title: Sunyaev–Zeldovich detection of hot intracluster gas at redshift 4.3

Author: Zhou, Dazhi, Chapman, Scott C., Aravena, Manuel, Araya-Araya, Pablo, Archipley, Melanie, Cathey, Jared, Deane, Roger P., Di Mascolo, Luca, Gobat, Raphael, Greve, Thomas R., Hill, Ryley, Kim, Seonwoo, Phadke, Kedar A., Pillai, Vismaya R., Posses, Ana C., Reichardt, Christian L., Solimano, Manuel, Spilker, Justin S., Sulzenauer, Nikolaus, Dike, Veronica J., Vieira, Joaquin D., Vizgan, David, Wang, George C. P., Wei, Axel

Issue&Volume: 2026-01-05

Abstract: Most baryons in present-day galaxy clusters exist as hot gas (107K), forming the intracluster medium (ICM)1. Cosmological simulations predict that the mass and temperature of the ICM decline towards earlier times, as intracluster gas in younger clusters is still assembling and being heated2,3,4. To date, hot ICM has been securely detected only in a few systems at or above z≈2, leaving the timing and mechanism of ICM assembly uncertain5,6,7. Here we report the direct observation of hot intracluster gas via its thermal Sunyaev–Zeldovich signature in the protocluster SPT2349–56 with the Atacama Large Millimeter/submillimeter Array. SPT2349–56 hosts a large molecular gas reservoir and three radio-loud active galactic nuclei (AGN) within an approximately 100-kpc region at z=4.3 (refs.8,9,10,11). The measurement implies a thermal energy of about 1061erg in the core, about 10 times more than gravity alone should produce. Contrary to current theoretical expectations3,4,12, the hot ICM in SPT2349–56 demonstrates that substantial heating can occur very early in cluster assembly, depositing enough energy to overheat the nascent ICM well before mature clusters become common at z≈2.

DOI: 10.1038/s41586-025-09901-3

Source: https://www.nature.com/articles/s41586-025-09901-3