近日，英国剑桥大学的Ignas Juodzbalis及其研究团队取得一项新进展。经过不懈努力，他们在早期宇宙中发现一个休眠的超大质量黑洞。相关研究成果已于2024年12月18日在国际权威学术期刊《自然》上发表。

本研究报道了从JADES调查中检测到的一个位于红移z=6.68的星系中宽泛的Hα发射线，该发射线追踪到了一个质量约为4×10⁸个太阳质量、且仅以爱丁顿极限0.02倍的速度吸积的黑洞。该黑洞与其宿主星系的恒星质量比约为0.4，即比本地关系高出约1000倍，然而，在宿主星系的动力学质量和速度弥散方面，该系统却更接近本地关系。

此天体很可能表明，在再电离时期前后，存在着一个数量大得多的休眠黑洞星族。其特性与以下情景相符：短暂的超级爱丁顿吸积爆发导致黑洞过度增长，并从吸积盘中大量排出气体；在爆发之间，黑洞大部分时间处于休眠状态。

据悉，近期的观测发现，在大爆炸后的最初几亿年里，就已经存在大量的超大质量黑洞，其中许多与本地关系相比，相对于其宿主星系的恒星质量而言似乎过大。为了解释这些发现，人们提出了几种不同的模型，从重的种子黑洞到经历高吸积率爆发的轻种子黑洞不等。然而，目前的数据集无法区分这些不同的场景。

附：英文原文

Title: A dormant overmassive black hole in the early Universe

Author: Juodbalis, Ignas, Maiolino, Roberto, Baker, William M., Tacchella, Sandro, Scholtz, Jan, DEugenio, Francesco, Witstok, Joris, Schneider, Raffaella, Trinca, Alessandro, Valiante, Rosa, DeCoursey, Christa, Curti, Mirko, Carniani, Stefano, Chevallard, Jacopo, de Graaff, Anna, Arribas, Santiago, Bennett, Jake S., Bourne, Martin A., Bunker, Andrew J., Charlot, Stphane, Jiang, Brian, Koudmani, Sophie, Perna, Michele, Robertson, Brant, Sijacki, Debora, bler, Hannah, Williams, Christina C., Willott, Chris

Issue&Volume: 2024-12-18

Abstract: Recent observations have found a large number of supermassive black holes already in place in the first few hundred million years after the Big Bang, many of which seem to be overmassive relative to their host galaxy stellar mass when compared with local relation. Several different models have been proposed to explain these findings, ranging from heavy seeds to light seeds experiencing bursts of high accretion rate. Yet, current datasets are unable to differentiate between these various scenarios. Here we report the detection, from the JADES survey, of broad Hα emission in a galaxy at z=6.68, which traces a black hole with a mass of about 4×10⁸M_⊙ and accreting at a rate of only 0.02 times the Eddington limit. The black hole to host galaxy stellar mass ratio is about 0.4—that is, about 1,000 times above the local relation—whereas the system is closer to the local relations in terms of dynamical mass and velocity dispersion of the host galaxy. This object is most likely an indication of a much larger population of dormant black holes around the epoch of reionization. Its properties are consistent with scenarios in which short bursts of super-Eddington accretion have resulted in black hole overgrowth and massive gas expulsion from the accretion disk; in between bursts, black holes spend most of their life in a dormant state.

DOI: 10.1038/s41586-024-08210-5

Source: https://www.nature.com/articles/s41586-024-08210-5