The emergence of massive black holes early on in the history of the Universe is a topic brought to the fore by recent JWST results. If these behemoths formed according to the conventional paradigm — with growth mechanisms taking place over billions of years — then how can there be as many as we now observe, already in existence so soon after the Big Bang? Roberto Maiolino and collaborators seek to shed light on this question, by analysing the JWST NIRSpec spectrum of the exceptionally luminous high-redshift galaxy GN-z11.

The authors deduce the presence of an accreting black hole in GN-z11 from the detection of key emission lines such as [NeIV] and CII^*, and a high gas density in line with broad line regions of black hole-hosting AGN. Also present is a deep blueshifted absorption trough of CIV, which could trace a high velocity outflow. With an inferred bolometric luminosity of the AGN of 10⁴⁵ erg s^–1 the object is consistent with the super-Eddington accretion scenario, one of the potential mechanisms to explain the rapid growth of supermassive black holes in the early Universe.

宇宙历史早期出现的大质量黑洞是 JWST 最近的结果引起关注的一个话题。如果这些庞然大物是根据传统范式形成的——生长机制发生了数十亿年——那么怎么可能有我们现在观察到的那么多，在大爆炸后这么快就已经存在了呢？Roberto Maiolino 和合作者试图通过分析异常明亮的高红移星系 GN-z11 的 JWST NIRSpec 光谱来阐明这个问题。

^{作者通过检测 [NeIV] 和 CII *}等关键发射线，推断 GN-z11 中存在吸积黑洞，并且气体密度高，与黑洞所在 AGN 的宽谱线区域一致。还存在 CIV 的深蓝移吸收槽，可以追踪高速流出。推测活动星系核的辐射光度为 10 ⁴⁵ erg s ^–1，该物体与超爱丁顿吸积情景一致，这是解释早期宇宙中超大质量黑洞快速增长的潜在机制之一。