THE discovery of a “binge-eating” black hole that is expelling powerful beams of material has shed new light on our neighbouring galaxies, according to new research from North East experts.
Using earth-orbiting X-ray telescopes, including NASA’s Swift, a team of astronomers led by Durham University watched as the X-ray emission from the black hole in our nearest neighbouring galaxy, Andromeda, brightened and faded over the course of six months.
The study, published in the scientific journal Nature, shows what happens when black holes feast rapidly on the material stripped from a companion star.
This is the first time that radio jets have been detected from a stellar-mass black hole outside our own Milky Way galaxy.
It is the second Ultraluminous X-Ray source (ULX) to have been spotted in Andromeda, which is more than two million light years away, in the past two years.
X-ray telescopes have shown how many nearby galaxies host ULXs, which can be bright enough to outshine an entire galaxy.
Astronomers have spent years debating whether these are black holes just a few times the mass of the sun which are gorging themselves on gas from an orbiting star, or whether they are more massive black holes eating more sedately.
Lead author Dr Matthew Middleton, who led the latest research at Durham University, said the findings helped solve this debate.
Dr Middleton said: “The black hole we observed in Andromeda is the missing link.
“Our observations tell us that this ULX source – and by extension, many others – is just a run-of-the-mill black hole, only about 10 times the mass of the sun, that is swallowing material as fast as it can.”
Dr Middleton added: “We watched a black hole go from nibbling daintily at an appetiser to bingeing on the main course, and then gradually slowing down over dessert.”
Black holes in our own Milky Way galaxy are very rarely seen to binge, but when they do, they also launch very powerful beams of material called jets, which are blasted outwards at close to the speed of light.
Despite the distance to Andromeda, the absence of dust and gas in that direction allows an unhindered view of the feast, giving scientists key new insights into how jets are produced.
This finding was confirmed by zooming in using the world’s most eagle-eyed radio telescope – the Very Long Baseline Array.
Co-author Dr Tim Roberts, in the Department of Physics, said: “We’ve had the ability to study ULXs for more than a decade, but it’s only because we had the good fortune that this object appeared in our local neighbourhood that we’ve been able to make these breakthrough observations and demonstrate this is a relatively small black hole.”