Astronomers have discovered the brightest object in the Universe – DW – 02/20/2024

All galaxies have a supermassive black hole at their center, an area that absorbs all surrounding matter while releasing enormous amounts of energy in the form of visible light and radio frequencies. These are quasars, the brightest and hottest objects in the Universe.

An international team has just discovered the brightest, most luminous quasar ever observed. Details of the discovery were published in a paper published in the journal Nature Astronomy.

Quasars get their energy from supermassive black holes. This record-breaking quasar’s black hole is so voracious that its mass is increasing by the equivalent of one Sun per day, making it the fastest-growing black hole discovered to date.

In addition, by collecting matter from their surroundings, quasars emit large amounts of light, which is visible even from Earth.

For this reason, the newly discovered quasar, which resides in the fastest-growing black hole known to date, “with the mass of 17 billion suns and which eats little more than one sun per day,” is also “the most famous in the universe.” says Christian Wolf, an astronomer at the Australian National University (ANU) and lead author of the study.

Astronomers made the discovery using the European Southern Observatory’s (ESO) Very Large Telescope (VLT).

According to their calculations, J0529-4351, as the quasar was named, is so far away that its light took more than 12 billion years to reach Earth. The matter pulled towards this disk-shaped black hole emits so much energy that J0529-4351 is more than 500 billion times brighter than the Sun.

“All this light comes from a hot accretion disk seven light years across,” which is about 15,000 times the distance from the Sun to Neptune’s orbit. “This must be the largest accretion disk in the Universe,” concludes Samuel Lai, a graduate student at ANU and co-author of the study.

Hidden in plain sight

But the most surprising thing for the authors is that this record-breaking quasar was hiding in plain sight. “It’s surprising that it wasn’t discovered until today, when we already know about a million less impressive quasars. Until now, it has literally been staring us in the face,” says Christopher Oncken, an astronomer at ANU and co-author. research.

And although the object appeared in ESO’s Schmidt Southern Sky Survey images back in 1980, it was not recognized as a quasar until decades later, Oncken admits.

Finding quasars requires accurate observational data over large swathes of the sky, but this amount of information can only be analyzed using machine learning models that search and distinguish quasars from other celestial objects.

But because these models are trained on existing data, they can make mistakes and classify discoveries as similar to those already known.

Thus, if the new quasar were brighter than any previously observed, the program could reject it and classify it as a star not too far from Earth.

uh (ap, efe, The Guardian)