Even among black holes that are known to devour anything that crosses their horizon, this one stands out for its great appetite.
Researchers from the Australian College of Science have just got their hands on a cosmic curiosity of crazy proportions; they have unearthed a huge black hole whose mass has been estimated at around three billion Suns… and it is still growing.
This simple observation is already enough to make it a very special object. Indeed, the majority of black holes of this caliber stopped growing several billion years ago. But this one doesn’t seem to want to stop swelling. Astronomers estimate that it is around 500 times larger than Sagittarius A*, the supermassive black hole that structures the Milky Way, the first image of which reached us recently (see our article).
To put this figure in this context, it means that the entire solar system could perfectly fit in the horizon of the black hole, this small dark zone at the center of the singularity from which nothing can escape.
An exceptionally voracious black hole
And as you might expect, this behemoth flaunts a gluttony never before seen on this scale. It is even the very first time that astronomers have discovered a black hole that is growing at such spectacular speed; they explain that it swallows the equivalent of a planet Earth… every second.
This gargantuan diet has led to its transformation into a qasar, a rather special subcategory of black hole. These objects are extremely luminous which behave like real cosmic beacons for astronomers.
The intensity of the radiation emitted is directly related to the amount of matter they ingest. and as you might expect with a glutton of this category, the fireworks are up to its appetite. With a magnitude of 14.5, it is quite simply the brightest quasar to have been spotted in the last 9 billion years. It is even so bright that an amateur can observe it, provided it is done in good conditions and with a quality telescope.
The offspring of a “catastrophic event”?
This significant discrepancy with the rest of the observed black holes suggests the existence of another external phenomenon that would be responsible for the difference. For researchers, the challenge is therefore to identify it. “We want to know why this black hole is so different; Did a catastrophic event occur?” suggests Christopher Onken, one of the researchers affiliated with the study, in a press release.
With his team, he has already formulated some initial leads. “Perhaps two galaxies collided, which could have “fed” the black hole by putting a lot of material at its disposal.”, explains Onken.
While waiting for new elements, the mystery remains intact. But this discovery is a great opportunity that will undoubtedly allow progress on this issue. And it had better be, because the chances of finding a better observational candidate are extremely slim.
It’s like looking for a needle in a huge haystack on the scale of the cosmos. And even if “astronomers have been hunting objects like this for more than 50 years”, dixit Onken, the candidates did not jostle at the gate. This discovery is therefore timely, because astronomers were beginning to no longer know where to turn.
“We’ve more or less run out of stretches of sky where objects like this might be hiding.”, explains Christian Wolf, member of the research team. “We are quite confident that this record will not be broken.“, he says in reference to his appetite and his exceptional luminosity.
The research paper is available here.