An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5

Abstract

Quasars are the most luminous non-transient objects known and as a result they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120 + 0641 at redshift z = 7.09 has remained the only one known at z > 7 for more than half a decade. Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 × 10 times the luminosity of the Sun and a black-hole mass of 8 × 10 solar masses. The existence of this supermassive black hole when the Universe was only 690 million years old-just five per cent of its current age-reinforces models of early black-hole growth that allow black holes with initial masses of more than about 10 solar masses or episodic hyper-Eddington accretion. We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman α emission line (the Gunn-Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

Formation of the First Stars and Black Holes

“…In this section we will also briefly discuss the growth, by accretion, of black hole seeds formed from Pop III stars and from direct collapse routes in light of the observational constraints currently posed by observations of bright QSOs at z > 5. The existence of extremely bright QSOs up to z > 7 Wu et al, 2015;Bañados et al, 2018) is in tension with BH formation scenarios in which BH seeds start out light, of order a hundred solar masses as natural for the Pop III scenario (Sect. 1), and then grow gradually by Eddingtonlimited accretion.…”

A beacon at the dawn of the Universe

“…Initially seen as mysterious sources of extreme luminosity, quasars are now known to be supermassive black holes that are voraciously consuming gas from their immediate surroundings, emitting large amounts of radiation in the process. On page 473, Bañados et al 2 report observations of the most distant quasar found so far. The light detected from this object was emitted when the Universe was a mere 690 million years old -just 5% of its current age.…”

“…As material in the disk is pulled towards the black hole, energy is released in the form of electromagnetic radiation and, in some cases, as beams of charged particles called jets. Bañados et al 2 report observations of the most distant quasar identified so far, the light of which was emitted when the Universe was only 5% of its current age. Universe started out in a hot, dense state, filled mostly with ionized hydrogen.…”

“…Restoration efforts are often restricted to small, localized scales. Large ecological-engineering projects aimed at producing regional-scale effects are few, and among these, China's mega-projects -most notably, the Grain for Green Project (GGP) 2 -stand out because of their unparalleled scale (27.8 million hectares of forest re-established as of 2013 across 26 Chinese provinces 3 ). Writing in Nature Sustainability, Tong et al 4 report that the positive effects of these tree-planting projects on vegetation growth can be detected using remote-sensing satellite imagery of a large region of southwestern China (the provinces of Guizhou, Guangxi and Yunnan), in an area associated with highly erodible landscapes called karst.…”

“…2). The project's goal was to convert land on mountainous terrain prone to erosion (cropland or scrubland) into forested landscapes (Fig.…”