Juodžbalis Ignas, Maiolino Roberto, Baker William M, Tacchella Sandro, Scholtz Jan, D'Eugenio 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 Stéphane, Jiang Brian, Koudmani Sophie, Perna Michele, Robertson Brant, Sijacki Debora, Übler Hannah, Williams Christina C, Willott Chris
Kavli Institute for Cosmology, University of Cambridge, Cambridge, UK.
Cavendish Laboratory - Astrophysics Group, University of Cambridge, Cambridge, UK.
Nature. 2024 Dec;636(8043):594-597. doi: 10.1038/s41586-024-08210-5. Epub 2024 Dec 18.
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 × 10M 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.
最近的观测发现，在大爆炸后的最初几亿年里就已经存在大量超大质量黑洞，与本地关系相比，其中许多黑洞相对于其宿主星系的恒星质量似乎过大。已经提出了几种不同的模型来解释这些发现，从重种子到经历高吸积率爆发的轻种子。然而，目前的数据集无法区分这些不同的情况。在此，我们报告在JADES巡天中探测到一个红移z = 6.68的星系中存在宽Hα发射，这追踪到一个质量约为4×10M且吸积率仅为爱丁顿极限0.02倍的黑洞。黑洞与宿主星系恒星质量之比约为0.4，即比本地关系高出约1000倍，而该系统在宿主星系的动力学质量和速度弥散方面更接近本地关系。这个天体很可能表明在再电离时期周围存在大量休眠黑洞。它的性质与以下情景一致：超爱丁顿吸积的短爆发导致黑洞过度生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。
