A ravenous black hole at the beginning of time?

Astronomers claimed Monday that they had discovered perhaps the hungriest and most luminous object in the visible universe: a supermassive black hole that was swallowing a star every day. That would be the mass equivalent of 370 suns per year disappearing down a cosmic gullet 11 billion years ago at the beginning of time.

Burp indeed.

In a article published in Nature AstronomyChristian Wolf of the Australian National University and his colleagues from Australia and Europe called the object at the center of a newly discovered quasar known as J0529-4351 “the fastest growing black hole in the universe.”

According to their estimates, this black hole is one of the most massive black holes ever found: 17 billion times as massive as the Sun.

But other astrophysicists doubted the result and questioned the methods used to estimate the new quasar's mass and brightness. They said the calculations were too uncertain to be conclusive. “They may be the right value, but I don't think other observers would be shocked if it turned out that the actual mass was slightly smaller,” says Daniel Holz, a theoretical astrophysicist at the University of Chicago.

“It seems like an extreme object,” he said. But he added: “I would be shocked if this turned out to be the most luminous quasar in the sky.”

Jenny Greene, professor of astrophysical sciences at Princeton University, called the result “cute.”

“It's nice to get the brightest out of something,” she said.

Yet she was with Dr. Holz agrees: “I don't think this brightness difference between this and other quasars is that great, and given the historical variability of quasars. It is not clear that this object is even brighter than the others.”

Chung-Pei Ma, an astrophysicist at the University of California, Berkeley, weighed in, saying the estimate of these black hole masses could be off by a factor of two or three, “too big to make me lose sleep over the viability of the prevailing cosmological models.”

This is a story about mind-boggling big numbers, no matter how it plays out.

“There's a weird game we play in astronomy where we're always looking for the biggest, the brightest, the youngest, the oldest, etc.,” said Dr. Holz in an email. “Record-breaking objects are an efficient way to learn more about the universe. Extremes help clarify the contours of a problem and help push our theories to (or beyond) their breaking points.”

It's the same with quasars and black holes. Quasars are distant objects that resemble stars in the sky. In the 1960s it was discovered that they radiated improbable streams of energy, surpassing all stars in the galaxy in which they were embedded.

Astronomers have since concluded that all this energy is produced by matter falling into giant black holes. Just as a bathtub cannot drain in an instant, matter can only disappear into the cosmic drain at a rate called the Eddington limit, depending on the size of the black hole. The rest are trapped in a kind of ominous turnstile, a swirling, sparking disk that radiates energy. That makes black holes, despite their name, the brightest objects in the universe.

Because they resemble stars, quasars are difficult to find in the sky. Dr. Wolf, a dedicated quasar hunter, said in an email that he enjoyed the hunt. “I feel like a kid again,” he wrote.

In this case, the quasar was hiding in plain sight in the database of the European Space Agency's Gaia spacecraft, which has mapped the locations and properties of billions of stars since its launch in 2013.

Dr. Wolf and his team identified it as a quasar after observing it with a telescope at the Siding Spring Observatory in Australia. Follow-up spectrographic measurements with the European Southern Observatory's Very Large Telescope at La Silla in Chile allowed them to estimate the size of the accretion disk and the speed of the gas within it.

From this they in turn were able to conclude that the black hole had about 17 billion solar masses and was gaining mass as fast as it could, at the Eddington limit, given its size or mass.

“This process alone releases radiant energy from the accretion disk that is equivalent to the energy released by between 365 and 640 trillion suns,” the astronomers wrote in their paper. They hope to do better soon with an improved version of a new high-resolution instrument called Gravity on the Very Large Telescope, and the upcoming European Extremely Large Telescope now being built in Chile.

Recognizing that all estimates of the masses of these distant black holes in the early Universe were indeed uncertain by a large margin, Dr. Wolf that the new instruments should be able to get a very well-defined image of the rotating storm disk leading to a precise black hole. mass. “This will check the scale we use to the highest and most extreme level, and it could help settle the debate about all these extrapolations we currently rely on,” he said. “This will certainly be an important step for cosmology.”

For comparison, the black hole at the center of the Milky Way is only four million times more massive than the Sun, and the black hole depicted at the center of the giant galaxy M87 in Virgo is 6.5 billion times more massive than the sun.

The recent detections of supermassive black holes in galaxies early in the universe's history, just a billion or two years after the Big Bang, have fueled debate about how they could grow so big so quickly. Astronomers have long theorized that when the universe was only about 100 million years old, it was littered with black holes as the first stars burned out, exploded and collapsed into black holes with masses several dozen times the mass of the Sun. In principle, over cosmic time they could evolve into the monsters that exist at the centers of almost all galaxies, by merging with other black holes, sucking in gas and occasionally eating a star that came too close .

At the observed growth rate, the quasar's black hole would have doubled every 30 million years, said Dr. Wolf, which would have increased the black hole's mass to 17 billion suns within three billion years of the Big Bang.

But it was unlikely, he continued, that black holes actually grew continuously at their maximum speed. He noted that black holes only occasionally reach their Eddington limit, when a party presents itself. Even larger black holes have been discovered in the early days of the universe by telescopes like the James Webb Space Telescope, but none are as luminous as J0529-4351.

That has led some astronomers to speculate that many of these black holes had primordial origins, older than stars and galaxies, and started out very massive.

“I have come to believe that black holes formed before galaxies, and that they were the seeds around which galaxies formed, rather than the other way around,” said Dr. Wolf.

“This was proposed decades ago, but was considered too crazy to become mainstream,” he said. But results from the new James Webb Space Telescope have breathed new life into this idea. “It's a very exciting time,” said Dr. Wolf.