It's hard to believe it, but he had previously flown under the radar.
Astronomers have identified a supermassive black hole that absorbs the equivalent of a Sun per day, at the heart of the most luminous quasar ever observed, according to a study published in the journal Nature.
“We have discovered the fastest growing black hole known to date.
It has a mass of 17 billion suns and
eats
a little more than one Sun per day,” explained Christian Wolf, an astronomer at the Australian National University (ANU) and lead author of the study, in a press release from the European Southern Observatory (ESO).
Invisible by definition, a supermassive black hole illuminates the core of the galaxy that shelters it through its activity.
This nucleus is called a quasar, which is one of “the brightest objects in our sky”.
There are around a million of them across the universe.
The one observed by the ESO's Very Large Telescope (the VLT, located in Chile) is even “the most luminous object in the known universe”, according to Christian Wolf.
Its light took 12 billion years to reach the VLT instruments, which makes it possible to date its existence to the primitive epoch of the Universe, in other words it is 13.8 billion years old.
500,000 billion times brighter than the Sun
This light “comes from a hot accretion disk”, which captures the matter, “which measures seven light years in diameter – it must be the largest accretion disk in the Universe”, specified Samuel Lai, doctoral student at ANU and also co-author of the study, cited by the press release.
Seven light years correspond to “15,000 times the distance” between the Sun and the orbit of Neptune.
This record-breaking quasar had, however, remained “hidden in plain sight” until then.
The light of J0529-4351, as it was named, had in fact been detected in the 1980s, recalls the study published Monday.
But an automatic analysis of data from the Gaia satellite, which maps the galaxy, had likened it to a very luminous star.
Researchers using the Siding Spring Observatory, in Australia, and then the VLT's X-shooter instrument, finally identified it last year as indeed being a quasar.
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The supermassive black hole it houses attracts a colossal amount of matter, accelerated to no less rapid speeds, emitting light that is 500,000 billion times brighter than the Sun, according to the ESO press release. .
The existence of such a massive and luminous object in the early Universe “is difficult to explain,” notes the study, which recalls the discovery of similar quasars in recent years.
Their existence each time assumes the rapid growth of a supermassive black hole, which the theory still has difficulty describing.
A black hole is supposed to be born following the explosion of a star at the end of its life, whose core then collapses in on itself.
It can grow by feeding on the surrounding matter, attracted by its gravitational field.
Scientists are wondering about the process at work that allows a black hole to become supermassive in a relatively short time in the young Universe.