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Astronomers have discovered the brightest known object in the universe, and it’s a quasar powered by the fastest-growing black hole ever measured, a new study shows. Initially classified as a star, the quasar managed to hide in plain sight until recently, surprising scientists.
Quasars are the luminous nuclei of distant, ancient galaxies. These shiny phenomena are undoubtedly the most dazzling objects in the cosmos – and scientists think they are powered by supermassive black holes that are the central engines of large galaxies.
When astronomers using the European Southern Observatory’s Very Large Telescope spied a quasar named J0529-4351, they discovered that the incredibly distant object is so far from our solar system that it takes light more than 12 billion years to reach Earth.
The black hole powering the quasar devours the equivalent of one sun per day and has a mass about 17 billion times that of our sun, the researchers found. A study detailing the staggering discovery was published Monday in the journal Nature Astronomy.
“The incredible growth rate also means the release of a huge amount of light and heat,” said lead author Christian Wolf, associate professor at the Australian National University’s College of Science, in a statement. “So this is also the brightest known object in the universe. It is 500 trillion times brighter than our sun.”
Astronomers are eager to study the quasar, as well as other elusive objects, with new instruments and observatories in the future, because distant supermassive black holes could answer important questions about the early days of the universe, such as how galaxies formed and evolved.
A black hole is an enormous source of energy
The intense gravitational influence of black holes pulls matter towards these celestial bodies in such an energetic way that light is created. The blinding radiation is caused by the black hole’s accretion disk, or the ring around the black hole where material collects before it is consumed.
“It looks like a gigantic and magnetic storm cell with temperatures of 10,000 degrees Celsius (18,032 degrees Fahrenheit), lightning everywhere and winds blowing so fast it would go around the Earth in a second,” Wolf said.
Astronomers know that if they observe an incredibly bright quasar, it means a fast-growing supermassive black hole is also present, and J0529-4351 is the most impressive yet on both counts.
“All this light comes from a hot accretion disk with a diameter of seven light-years – this must be the largest accretion disk in the universe,” says co-author Samuel Lai, PhD student at the Research School of Astronomy & Australian National University. Astrophysics, in a statement.
Hide in plain sight
Wolf said he’s not sure J0529-4351’s records can ever be broken. Although another team of scientists reported that the Hubble Space Telescope spotted a quasar as bright as 600 trillion suns in 2019, the object’s brightness was enhanced by gravitational lensing, a phenomenon in which clusters of galaxies help magnify objects in the distant universe. The actual brightness of the quasar, named J043947.08+163415.7, is believed to be closer to about 11 trillion suns, according to the researchers who made the initial discovery.
The quasar first appeared in images from the European Southern Observatory’s Schmidt Southern Sky Survey in 1980, but was not recognized as a quasar.
“It’s a surprise that it has remained unknown to this day, when we already know about a million less impressive quasars. It has literally looked us in the eye so far,” says co-author Dr. Christopher Onken, research fellow at the Research School of Astronomy & Astrophysics at the Australian National University, said in a statement.
Searching for quasars is an imperfect science
Searching for clues in large sky surveys is the best way to find distant quasars, but the massive data sets generated by these massive surveys often need to be fed into machine learning models for analysis. The computer models can only pick out quasar candidates that resemble known objects because the software is trained on existing data.
Newly discovered quasars may be brighter than those observed in the past, meaning computer models can reject the objects by classifying them as bright nearby stars.
This misidentification is what initially happened to J0529-4351 when an automated program analyzing data from the European Space Agency’s Gaia satellite categorized the object as a star in June 2022.
But astronomers determined the object was a quasar when they observed it in 2023 using the 2.3-meter telescope at the Australian National University’s Siding Spring Observatory near Coonabarabran in New South Wales. The team followed observations from the powerful Very Large Telescope in Chile’s Atacama Desert to confirm details about the black hole, including its enormous mass.
“Personally, I just love the chase,” Wolf said. “For a few minutes a day I feel like a kid playing treasure hunt again, and now I bring to the table everything I’ve learned since then.”
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