Scientists have discovered compelling evidence that the nearest supermassive Black Hole outside our Milky Way Galaxy is located in this galaxy. This stealthy black hole, nestled in the Large Magellanic Cloud(LMC), our closest galactic neighbor, had long been elusive. Researchers have been able to trace its signs using a cast of unusual hypervelocity star thanks to advanced mapping and high-precision modeling.
Scientists tracked 21 stars moving at hypervelocity on the Milky Way fringes. The stars are traveling so fast that they will escape from the Milky Way’s gravitational pull and other nearby galaxies. The researchers determined the stars’ origins by analysing their trajectory, much like forensic specialists tracing a bullet.
The researchers found this to be remarkable. They estimated that about half of the hypervelocity star had come from Sagittarius, the supermassive Black Hole in our Milky Way. The remaining stars, however pointed at an unanticipated source – a supermassive LMC black hole that was previously unknown.
It’s amazing to think that there is another black hole supermassive just around the corner, cosmologically speaking.” Harvard & Smithsonian (CfA), who led the study. Black holes can be so sneaky, this particular one was practically right under our noses.
Data from Gaia, the European Space Agency satellite that maps over a million stars in stunning detail, made this discovery possible. These data, combined with an improved understanding of LMC’s orbit about the Milky Way enabled researchers to develop new theoretical models that track how hypervelocity star are launched.
The neighboring galaxy slowly pulls our galaxy.
When a system of two stars gets too close to an ultramassive blackhole, hypervelocity star formation occurs. Massive gravitational force tears the two apart and flings one star out of the galaxy with millions of miles an hour. By combining Gaia data and our models, Kareem el-Badry from Caltech explained that they identified a cluster hypervelocity star which could have only come about as a result of a black hole supermassive in the LMC.
Researchers calculated that the LMC’s black hole mass is about 600,000.0 times our Sun. Although it is massive, Sagittarius A* – the Milky Way supermassive Black Hole – which has a mass of about 4,000,000 solar masses, pales in comparison. Some supermassive dark holes in other parts of the universe are larger than billions solar masses.
Artist’s rendition of an ejected hypervelocity-star from the Large Magellanic Cloud. The intense gravitational force that occurs when a binary system of stars gets too close to the supermassive hole can tear them apart. The black hole captures one star into an orbital path, and the other star is launched outwards at speeds exceeding millions of miles per hours. This is how hypervelocity stars are created. In the inset, the orbital paths of the binary are shown in interwoven lines. One star is captured by the blackhole (at the center), while the other one is ejected out into space.
Credit: CfA/Melissa Weiss
The study’s key component was predicting the LMC’s black hole, based on the Milky Way and its relative motion to it, would emit hypervelocity star in a certain pattern. Researchers found a cluster of the speedy stars where they had predicted.
The discovery opens a whole new chapter in our knowledge of black holes, and it raises fascinating questions about galaxies that are close to each other. The only way to explain this data, said Scott Lucchini of CfA and co-author of the paper. It’s not only the Milky Way supermassive Black Hole that is removing stars, but our neighboring black hole does the same.
The researchers’ findings have been accepted by The Astrophysical Journal for publication, laying the foundation for future explorations of this cosmic giant. We may learn more about hidden forces in our galaxy’s neighborhood as astronomers improve their observations and refine models.
Journal Reference
- Hypervelocity Stars Trace Supermassive black Hole in Large Magellanic Cloud by Jiwon Han, et. al. The Astrophysical Journal (2025). On arXiv: DOI: 10.48550/arxiv.2502.00102
