(ORDO NEWS) — A first-of-its-kind “missing link” object discovered in the early universe could solve the mystery of the oldest supermassive black holes, scientists say.
The discovery of GNz7q, a black hole dating only 750 million years after the Big Bang, is consistent with theoretical predictions of what the “ancestor” of supermassive black holes might look like – and while we’ve never seen this object before, there could be many more such holes.
“It’s unlikely that the discovery of GNz7q… was just ‘stupid luck’,” says astronomer Gabriel Brammer of the University of Copenhagen in Denmark.
“The prevalence of such sources may actually be significantly higher than previously thought.”
GNz7q, red dot in the center of the inset, in the GOODS-North Hubble field. (NASA, ESA, Garth Illingworth [Santa Cruz University], Pascal Hoesch [Santa Cruz University, Yale], Richard Bouvens [LEI], I. Labbe [LEI], Cosmic Dawn Center / Niels Bohr Institute / University of Copenhagen , Denmark)
The period to which GNz7q belongs is known as Cosmic Dawn, an epoch lasting from about 50 million years after the Big Bang to 1 billion years, when the earliest celestial objects were formed, including baby stars and nascent galaxies.
At some point in these initial stages of the evolution of the universe, supermassive black holes appeared. But when and how this happened remains an open question in astrophysics.
Last year, scientists announced the discovery of J0313-1806, the most distant quasar at more than 13 billion light-years from Earth and the oldest supermassive black hole ever discovered.
But where did something like J0313-1806 come from? Or rather, what were the evolutionary precursors of supermassive black holes in the early stages of the universe?
Theoretically speaking, scientists have some ideas.
“The simulations show an evolutionary sequence of dust-reduced quasars emerging from highly dusty stellar flares, which then transition into dust-free luminous quasars, ejecting gas and dust,” the researchers explain in a new study led by first author and astronomer Seiji Fujimoto, also from the University of Copenhagen.
“Although the last phase has been identified up to redshift 7.6 [meaning J0313-1806], no transient quasar has been found.”
So far, that is. Fujimoto, Brammer and colleagues identified GNz7q by analyzing archived observational data from the Hubble Space Telescope. It seems that this object is the very elusive ancestor that scientists were trying to find.
Surprisingly, this “missing link” black hole has been discovered in a comprehensively studied region of the night sky – as part of the Great Observatories Origins Deep Survey (GOODS) – but only now has spectral analysis been able to determine what most likely represents the luminosity of GNz7q .
“Our analysis suggests that GNz7q is the first example of a rapidly growing black hole in the dusty core of a stellar galaxy at an epoch close to the earliest supermassive black hole known in the universe,” says Fujimoto.
“The properties of the object across the entire electromagnetic spectrum are in excellent agreement with the predictions of theoretical modeling.”
The host galaxy GNz7q is incredibly active, producing about 1,600 solar masses of stars per year, or at least it was around 13 billion years ago when this ancient light was emitted, the researchers say.
The emission pattern of GNz7q matches the profile of a transitional black hole, since its ultraviolet brightness (representing radiation from the outer part of the black hole’s accretion disk) matches the absence of X-ray emission (which would have been generated in the core of the disk, but obscured by the current dusty conditions of an early stellar galaxy, from which GNz7q evolved).
As the researchers explain, these characteristics are ideal for a black hole designed for supermassive things.
“Its properties are in perfect agreement with the transitional phase of the evolutionary paradigm of supermassive black holes,” the team explains in their paper. “A low-luminosity quasar clouded by dust, emerging in vigorously bursting star formation”.
In other words, this is what we predicted the precursor of a supermassive black hole to look like about 13 billion years ago, when its light finally reached us, traveling about 13 billion light years.
Due to the phenomenon of the expansion of the universe, GNz7q – in whatever final, supermassive form it is now – would be about twice as far away from us today, at a distance of about 25 billion light years.
It remains only to guess how brightly it glows now?
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