NASA’s Webb Reveals Black Hole That Formed Before Its Galaxy

Space telescope image showing hundreds of bright objects of different size, color, and shape on the black background of space. Colors range from white to deep red. Shapes include elliptical, spiral, dot-like, dash-like, and arcuate. Many of the large objects near the center of the image are fuzzy white, with bright white cores. Many smaller objects scattered throughout the image are pink to red. Three objects in the central part of the image are called out with small white boxes: A box labeled “C” at about 12 o’clock; one labeled “B” at 3 o’clock; and a box labeled “A” at 4 o’clock. Images of the three objects are enlarged in boxes running vertically along the right. From top to bottom these are labeled QSO1A, QSO1B, and QSO1C. At the center of each box is a tiny, circular red dot. QSO1A (top) is notably larger, brighter, and clearer than the other two. QSO1B, in the middle, is smallest and fuzziest, and is somewhat washed out by the light of a larger white object next to it. — An image from NIRCam (the Near Infrared Camera) on NASA’s James Webb Space Telescope shows Abell2744-QSO1, magnified and triply imaged by galaxy cluster Abell 2744. Abell2744-QSO1 (QSO1) is a prototypical Little Red Dot, one of the first of now hundreds of tiny glowing flecks of infrared light that Webb has found speckling the early universe. Image: NASA, ESA, CSA, Lukas Furtak (Ben-Gurion University); Image Processing: Alyssa Pagan (STScI)

Which comes first, the galaxy or the black hole? We don’t know, but scientists have long thought it could be the galaxy: Large stars within an existing galaxy consume their fuel and collapse to form black holes, which can gobble up surrounding material and merge over time to form more massive entities.

But it’s hard to figure out how black holes millions to billions of times the mass of the Sun, thousands of which have now been detected in the early universe, could have grown so quickly from such small seeds.

Now, researchers using NASA’s James Webb Space Telescope have detected clear evidence that some supermassive black holes were enormous from the beginning, forming without a stellar collapse phase, and without a significantly more massive host galaxy to feed them.

“This is a remarkable finding,” said Roberto Maiolino of University of Cambridge in the United Kingdom, co-author of studies published in Nature and the Monthly Notices of the Royal Astronomical Society. “It’s a paradigm shift, a total revisiting of the classical scenarios of how black holes form and grow.”

Mapping gas composition, velocity

The team recognized that if QSO1’s black hole is as massive as it looks, they should be able to use the integral field unit (IFU) on Webb’s NIRSpec (Near Infrared Spectrograph) to trace the effects of its gravity on the gas swirling around it, while also mapping the distribution of various elements in the gas.

Cambridge graduate student Ignas Juodžbalis and Cosimo Marconcini of the University of Florence, lead authors on one of the studies, used the IFU observations to map motions of hydrogen gas surrounding the black hole. When they plotted the rotation velocity as a function of distance from the center, they found that the gas has Keplerian motion: It orbits a central point in the same way that planets in our solar system orbit the Sun.

“This is important because it tells us that most of the mass of QSO1 is concentrated in the black hole at the center,” said Juodžbalis. “If the mass were more distributed, as it would be if there were a lot of stars, the gas would not have this perfect Keplerian rotation.”

Since Keplerian motion is governed by simple laws of gravity, the team was able to use the gas velocity measurements to calculate the black hole mass directly, a feat that had not previously been possible.

They found that not only is the black hole immense — roughly 50 million solar masses — it makes up, at minimum, an astonishing two-thirds of QSO1’s total mass. This proportion is thousands of times greater than in nearby galaxies, where supermassive black holes make up only a tiny fraction of the host galaxy’s total mass.

The IFU composition maps supported these results, showing that the gas throughout QSO1 is almost entirely hydrogen and helium, with very little of the heavier elements like oxygen that would be expected in a galaxy rich with stars and stellar debris. With a metallicity less than 0.5% of the Sun, QSO1 is one of the most pristine galactic environments ever measured.

“This is a phenomenal result,” said Maiolino. “It is the first direct measurement of a black hole mass within the first billion years after the big bang, and it is consistent with the previous measurements.” The team thinks this is a good sign that the assumptions used for indirect mass measurements are valid and the masses of other black holes in the early universe have not been overestimated.

Supermassive black hole origins

The outsized mass of QSO1 relative to its host galaxy suggests that it can’t have formed gradually from much smaller, stellar-mass black holes merging and feeding. “It seems that we have found a black hole that does not have a substantial host galaxy and that has predated stellar processes,” said Juodžbalis. “This is very exciting because it is evidence for primordial black holes or direct collapse black holes, which have been theorized but not confirmed.”

Whether QSO1’s black hole evolved from a “heavy seed” that formed within the first second of the big bang or somewhat later from the collapse of a giant cloud of gas, it was almost certainly born big, and may be in the early stages of building a galaxy around it.

The team thinks that Little Red Dots like QSO1 cannot have been rare in the early universe, and is in the process of analyzing similar objects to find out whether supermassive black holes actually do predate the galaxies where they currently reside.

View the full NIRCam image and explore the observation on Space Telescope Live.