A hidden black hole may exist in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way. Evidence has emerged through the discovery of hypervelocity stars at the edge of the Milky Way, which appear to have been propelled by a yet-undetected supermassive black hole within the LMC. These runaway stars, moving at extraordinary speeds, were tracked using data from the European Space Agency’s Gaia satellite. The findings suggest that while some of these stars were accelerated by the Milky Way’s own black hole, Sagittarius A (Sgr A), a significant number appear to have been ejected from the LMC, pointing to the presence of a massive gravitational force in that region.
Evidence from Hypervelocity Stars
According to a study accepted for publication in The Astrophysical Journal, researchers analysed 21 hypervelocity stars that are on course to exit the Milky Way. Tracing their origins, the team determined that nearly half of these stars were flung from the Milky Way’s core, but the remaining stars followed a trajectory linked to the LMC. This led scientists to theorise that a supermassive black hole within the LMC may have played a role in accelerating them.
Jesse Han, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian (CfA), told Space.com that the possibility of another supermassive black hole in close proximity to the Milky Way is striking. He noted that black holes are often difficult to detect, making this discovery particularly significant.
Potential Mass and Implications
The mass of this hidden black hole has been estimated at around 600,000 times that of the Sun, based on the number and speed of stars ejected from the LMC. Though smaller than Sagittarius A*, which is 4.3 million times the Sun’s mass, it fits within the expected range for supermassive black holes.
Scott Lucchini, a researcher at CfA, said that the findings suggest the Milky Way may not be the only galaxy in the vicinity ejecting stars due to the gravitational influence of a supermassive black hole. The study’s conclusions align with previous theories predicting the presence of hypervelocity stars as a signature of an unseen black hole in the LMC.
