Hubble reveals bizarre, evolutionarily missing links from the morning of the universe

This is an artist’s illustration of a supermassive black hole inside the dust-clad core of a powerful star-forming “star eruption” galaxy. It will eventually become an extremely light quasar when the dust is gone. The research team believes that the object, discovered in a Hubble study of deep-sky, may be the evolutionary “missing link” between quasars and starburst galaxies. The dusty black hole dates back to just 750 million years after the big bang. Credit: NASA, ESA, N. Bartmann

Bizarre, evolutionarily missing links uncovered in the Hubble Deep Survey of Galaxies

The universe is so saturated with galaxies that even the strangest things can go unnoticed for years to come. GNz7q in the Hubble GOODS-North field

An international team of astronomers using archival data from NASA’s Hubble Space Telescope and other space and Earth-based observatories has discovered a unique object in the distant universe that is a crucial link between young star-forming galaxies and the earliest supermassive black holes. This object is the first of its kind to be discovered when the universe was only 750 million years old. It had lurked unnoticed in one of the best-studied areas of the night sky. The object, referred to as GNz7q, is the red dot in the center of the image of the Hubble Great Observatories Origins Deep Survey-North (GOODS-North). Credit: NASA, ESA, Garth Illingworth (UC Santa Cruz), Pascal Oesch (UC Santa Cruz, Yale), Rychard Bouwens (LEI), I. Labbe (LEI), Cosmic Dawn Center / Niels Bohr Institute / University of Copenhagen, Denmark

Hubble sheds light on the origins of supermassive black holes

Astronomers have identified a rapidly growing black hole in the early universe that is considered a crucial “missing link” between young star-forming galaxies and the first supermassive black holes. They used data from NASA’s Hubble Space Telescope to make this discovery.

Until now, the monster, nicknamed GNz7q, had lurked unnoticed in one of the best-studied areas in the night sky, the Great Observatories Origins Deep Survey-North (GOODS-North) field.

Archived Hubble data from the Hubble Advanced Camera for Surveys helped the team determine that GNz7q existed only 750 million years after the big bang. The team obtained evidence that GNz7q is a newly formed black hole. Hubble found a compact source of ultraviolet (UV) and infrared light. This could not be caused by emission from galaxies, but is consistent with the expected radiation from materials falling on a black hole.

Fast-growing black holes in dusty, early star-forming galaxies are predicted by theories and computer simulations, but had not been observed until now.

“Our analysis suggests that GNz7q is the first example of a fast-growing black hole in the dusty core of a shooting star galaxy in an era close to the earliest supermassive black hole known in the universe,” explained Seiji Fujimoto, an astronomer at Niels Bohr. Department of the University of Copenhagen and lead author of Nature paper describing this discovery. “The properties of the object across the electromagnetic spectrum are in excellent agreement with predictions from theoretical simulations.”

One of the unique mysteries in astronomy today is: How did supermassive black holes weighing millions to billions of times the mass of the Sun become so large so fast?

Current theories predict that supermassive black holes begin their lives in the dust-enveloped nuclei of powerful star-forming “starburst” galaxies before emitting the surrounding gas and dust and appearing as extremely luminous quasars. Although extremely rare, both these dusty shooting galaxies and luminous quasars have been discovered in the early universe.

The team believes that GNz7q may be a missing link between these two classes of objects. GNz7q has exactly both aspects of the dusty shooting star galaxy and the quasar, where the quasar light shows the dust red color. In addition, GNz7q lacks various properties normally observed in typical, very luminous quasars (similar to the emission from the accretion disk of the supermassive black hole), which most likely explains why the central black hole in GN7q is still in a young and less massive phase. These properties match perfectly with the young transition phase quasar that has been predicted in simulations but never identified by similarly high redshift universes as the very luminous quasars hitherto identified up to a redshift of 7.6.

“GNz7q provides a direct link between these two rare populations and provides a new path to understand the rapid growth of supermassive black holes in the early days of the universe,” Fujimoto continued. “Our discovery provides an example of precursors to the supermassive black holes we observe in later eras.”

While other interpretations of the team data cannot be completely ruled out, the observed properties of GNz7q are in strong agreement with theoretical predictions. GNz7q’s host galaxy forms stars at a rate of 1,600 solar masses per year, and GNz7q itself appears bright at UV wavelengths, but very faint at X-ray wavelengths.

In general, the growth disk in a solid black hole should be very bright in both UV and X-ray light. But this time, even though the team discovered UV light with Hubble, X-ray light was invisible even with one of the deepest X-ray data sets. These results suggest that the core of the accretion disk where X-rays originate is still hidden; while the outer part of the growth disk, from which UV light originates, becomes blurred. This interpretation is that GNz7q is a fast-growing black hole that is still hidden by the dusty core of its star-forming host galaxy.

“GNz7q is a unique discovery found right in the middle of a famous, well-researched sky – it shows that great discoveries can often be hidden right in front of you,” commented Gabriel Brammer, another astronomer at the Niels Bohr Institute. from the University of Copenhagen and a member of the team behind this result. “It is unlikely that the discovery of GNz7q within the relatively small GOODS-North study area was just ‘stupid luck’, but rather that the prevalence of such sources may actually be significantly higher than previously thought.”

It was only possible to find GNz7q hiding in plain sight, thanks to the uniquely detailed multi-wavelength datasets available for GOODS-North. Without this wealth of data, GNz7q would have been easy to overlook as it lacks the characteristics commonly used to identify quasars in the early universe. The team now hopes to systematically search for similar objects using dedicated high-resolution studies and to take advantage of NASA’s James Webb Space Telescope’s spectroscopic instruments to study objects like GNz7q in unprecedented detail.

“Complete characterization of these objects and probing of their evolution and underlying physics in much greater detail will be possible with the James Webb Space Telescope,” Fujimoto concluded. “Once in normal operation, Webb will have the power to determine how common these fast-growing black holes really are.”

Reference: “A dusty compact object that bridges galaxies and quasars at cosmic dawn” by S. Fujimoto, GB Brammer, D. Watson, GE Magdis, V. Kokorev, TR Greve, S. Toft, F. Walter, R Valiante, M. Ginolfi, R. Schneider, F. Valentino, L. Colina, M. Vestergaard, R. Marques-Chaves, JPU Fynbo, M. Krips, CL Steinhardt, I. Cortzen, F. Rizzo og PA Oesch, April 13, 2022, Nature.
DOI: 10.1038 / s41586-022-04454-1

The Hubble Space Telescope is an international collaboration between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, DC

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