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45 ASTRO PUBLISHING “GNz7q provides a direct connec- tion between these two rare popu- lations and provides a new avenue towards understanding the rapid growth of supermassive black holes in the early days of the Universe,” continued Fujimoto. “Our discovery is a precursor of the supermassive black holes we observe at later epochs.” Whilst other interpretations of the team’s data cannot be completely ruled out, the observed properties of GNz7q are in strong agreement with theoretical predictions. GNz7q’s host galaxy is forming stars at the rate of 1600 solar masses of stars per year and GNz7q itself ap- pears bright at ultraviolet wave- lengths but very faint at X-ray wavelengths. The team have interpreted this — along with the host galaxy’s bright- ness at infrared wavelengths — to suggest that GNz7q is harbors a rap- idly growing black hole still ob- scured by the dusty core of its accretion disc at the center of the star-forming host galaxy. As well as GNz7q’s importance to the understanding of the origins of su- permassive black holes, this discov- ery is noteworthy for its location in the Hubble GOODS North field, one of the most highly scrutinised areas of the night sky. “GNz7q is a unique discovery that was found just at the centre of a fa- mous, well-studied sky field — show- ing that big discoveries can often be hidden just in front of you,” com- mented Gabriel Brammer, another astronomer from the Niels Bohr In- stitute of the University of Copen- hagen and a member of the team behind this result. “It’s unlikely that discovering GNz7q within the rela- tively small GOODS-N survey area was just ‘dumb luck’ rather the prevalence of such sources may in fact be significantly higher than pre- viously thought.” Finding GNz7q hiding in plain sight was only possible thanks to the uniquely detailed, multi-wavelength datasets available for GOODS-North. Without this richness of data GNz7q would have been easy to overlook, as it lacks the distinguishing features usually used to identify quasars in the early Universe. The team now hopes to systemati- cally search for similar objects using dedicated high-resolution surveys and to take advantage of the NASA/ESA/CSA James Webb Space Telescope’s spectroscopic instru- ments to study objects such as GNz7q in unprecedented detail. “Fully characterising these objects and probing their evolution and un- derlying physics in much greater de- tail will become possible with the James Webb Space Telescope.” con- cluded Fujimoto. “Once in regular operation, Webb will have the power to decisively determine how common these rapidly growing black holes truly are.” JULY-AUGUST 2022 A rtist’s impression of GNz7q, the first such rapidly growing black hole to be found in the early Uni- verse. [ESA/Hubble, N. Bartmann] !