The Astronomers recently claimed to have discovered what could be the hungriest, most luminous object in the visible universe—a supermassive black hole that was swallowing a star a day. That would be the mass equivalent to 370 suns a year disappearing into a cosmic sinkhole 11 billion years ago at the beginning of time.
In a paper published in Nature Astronomy, Christian Wolf of the Australian National University and colleagues from Australia and Europe called the object at the center of a newly discovered quasar, J0529-4351, “the fastest-growing black hole in the universe.” ”.
According to their estimates, this black hole was one of the most massive ever found: 17 billion times the mass of the Sun. But other astrophysicists have questioned the methods by which the mass and luminosity of the quasar had been estimated, and said that the calculations were too uncertain to be conclusive.
“It does look like an extreme object,” said Daniel Holz, a theoretical astrophysicist at the University of Chicago. But he added: “I would be surprised if this turned out to be the brightest quasar in the sky.
“We play a strange game in astronomy, where we are always looking for the biggest, the brightest, the youngest, the oldest, etc.,” he wrote via email.
Quasars look like stars. They emit improbable torrents of energy, outshining all the stars in the galaxy in which they are embedded. Astronomers have concluded that all this energy is produced when matter falls into giant black holes. Just as a bathtub cannot be emptied in an instant, matter can disappear down the cosmic drain only at a certain rate, called the Eddington limit, which depends on the size of the black hole. The rest is trapped in a rotating disk that radiates energy. That makes black holes, despite their name, the brightest objects in the universe.
Wolf and his team identified J0529-4351 as a quasar after observing it with a telescope at the Siding Spring Observatory in Australia. Follow-up spectrographic measurements with the Very Large Telescope in Chile allowed them to estimate the size of the accretion disk and the velocity of the gas inside it.
This, in turn, led them to conclude that the black hole was about 17 billion solar masses and was accreting mass at the Eddington limit.
“In this process, its accretion disk alone releases radiative energy equivalent to the production of between 365 and 640 million million suns,” the astronomers wrote in their article.
By comparison, the black hole at the center of the Milky Way is only 4 million times the mass of the Sun.
Recognizing that all estimates of these distant masses of the universe's early black holes were uncertain by a wide margin, Wolf said that new instruments—including a high-resolution instrument called Gravity on the Very Large Telescope, and the upcoming Extremely Large Telescope that is being built in Chile—should be able to obtain a well-defined image of the rotating storm disk, leading to an accurate mass of the black hole.
Wolf said black holes only intermittently reach their Eddington limits, when a feast occurs. Telescopes like the James Webb Space Telescope have discovered even more massive black holes in the early universe, but none are as luminous as J0529-4351.
This has led some astronomers to speculate that many of these black holes had primordial origins, prior to stars and galaxies, and started out very massive.
“I myself am coming around to the idea that black holes formed before galaxies, and that they were the seeds around which galaxies formed and not the other way around,” Wolf said. “This was proposed decades ago, but was considered too crazy to become widespread.”
By: DENNIS OVERBYE
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/7143291, IMPORTING DATE: 2024-03-06 02:48:03
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