Unprecedented discovery: Black hole outside galaxy centre detected
Astronomers have discovered two massive black holes in a galaxy located 600 million light years away. This marks the first instance where one of them is found outside the centre of the galaxy.
Main highlights
- Two massive black holes have been discovered in one galaxy.
- One of the black holes is located outside the centre of the galaxy.
- The AT2024tvd phenomenon was detected in August 2024.
Astronomers from the University of California, Berkeley, have made an extraordinary discovery. In a galaxy located 600 million light years from Earth, two massive black holes have been identified. Remarkably, one of them is situated outside the galaxy's centre, a rarely observed phenomenon.
The AT2024tvd phenomenon, which enabled this discovery, was observed on 25 August 2024 by the Zwicky Transient Facility. This led to the detection of a second black hole, with a mass of approximately 1 million solar masses. It is positioned 2,600 light years from the centre of the galaxy.
This discovery is significant for further research on black holes. As explained by Yuhan Yao from the University of California, the classic location for such objects is the centre of the galaxy. However, this time, it has been possible to identify a black hole in an atypical location.
Yao emphasised that this case is located 2,600 light years from the centre. It is the first optically discovered case of a TDE phenomenon not in the centre of the galaxy.
Tidal disruption event
The second detected black hole was hiding in the outer regions of the central bulge of the galaxy. Astronomers found its trace thanks to the light radiation caused by the destruction of a star. As a result of the tidal forces exerted by the black hole, the star was stretched into a stream of matter, part of which began to fall into the black hole, generating radiation in the process.
The existence of a massive black hole wandering alone through the galaxy has two possible explanations. It may have originated from the nucleus of a small galaxy that was previously absorbed by a larger one and now either moves on a trajectory that is ejecting it from the galaxy or has been bound in an orbit that may eventually lead it to merge with the supermassive black hole at the centre. The second scenario suggests that there were three black holes in the centre of the galaxy, two of which merged, with the third being expelled to a further region of the galaxy.
