Brightest Object in the Universe Discovered – Powered by Supermassive Black Hole Eating a Sun a Day
Astronomers using the ESO’s VLT have discovered the brightest and most luminous quasar ever observed, powered by the fastest-growing black hole known, which accumulates mass at the rate of one Sun per day.
Record-Breaking Quasar
Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT), astronomers have characterized a bright quasar, finding it to be not only the brightest of its kind, but also the most luminous object ever observed. Quasars are the bright cores of distant galaxies and they are powered by supermassive black holes. The black hole in this record-breaking quasar is growing in mass by the equivalent of one Sun per day, making it the fastest-growing black hole to date.
The black holes powering quasars collect matter from their surroundings in a process so energetic that it emits vast amounts of light. So much so that quasars are some of the brightest objects in our sky, meaning even distant ones are visible from Earth. As a general rule, the most luminous quasars indicate the fastest-growing supermassive black holes.
Massive and Luminous Quasar
Astronomers have characterized the most luminous quasar observed to date, which is powered by the fastest-growing black hole. This black hole is growing in mass by the equivalent of one Sun per day. The matter being pulled in toward this black hole forms a disc that measures seven light-years in diameter — about 15,000 times the distance from the Sun to the orbit of Neptune.
"We have discovered the fastest-growing black hole known to date. It has a mass of 17 billion Suns, and eats just over a Sun per day. This makes it the most luminous object in the known Universe," says Christian Wolf, an astronomer at the Australian National University (ANU) and lead author of the study published today in Nature Astronomy. The quasar, called J0529-4351, is so far away from Earth that its light took over 12 billion years to reach us.
Hidden in Plain Sight
And, remarkably, this record-breaking quasar was hiding in plain sight. "It is a surprise that it has remained unknown until today, when we already know about a million less impressive quasars. It has literally been staring us in the face until now," says co-author Christopher Onken, an astronomer at ANU. He added that this object showed up in images from the ESO Schmidt Southern Sky Survey dating back to 1980, but it was not recognized as a quasar until decades later.
Finding quasars requires precise observational data from large areas of the sky. The resulting datasets are so large that researchers often use machine-learning models to analyze them and tell quasars apart from other celestial objects. However, these models are trained on existing data, which limits the potential candidates to objects similar to those already known. If a new quasar is more luminous than any other previously observed, the program might reject it and classify it instead as a star not too distant from Earth.
Discovery and Future Research
An automated analysis of data from the European Space Agency’s Gaia satellite passed over J0529-4351 for being too bright to be a quasar, suggesting it to be a star instead. The researchers identified it as a distant quasar last year using observations from the ANU 2.3-meter telescope. Discovering that it was the most luminous quasar ever observed, however, required a larger telescope and measurements from a more precise instrument. The X-shooter spectrograph on ESO's VLT in the Chilean Atacama Desert provided the crucial data.
The fastest-growing black hole ever observed will also be a perfect target for future research. Upgrades to ESO’s VLT Interferometer (VLTI) and the construction of the Extremely Large Telescope (ELT) in the Chilean Atacama Desert will make identifying and characterizing such elusive objects even more feasible. These efforts could shed light on the formation and evolution of supermassive black holes and their host galaxies in the early Universe.
