Black holes are commonly classified into two main types: supermassive black holes found at the centers of large galaxies, and lighter black holes with a mass less than 100 times that of the Sun. However, intermediate-mass black holes (IMBHs) have been hard to detect and are seen as crucial pieces missing in the evolution of black holes.
In a groundbreaking research effort, a team of astronomers from around the world examined more than 500 images captured by NASA’s Hubble Space Telescope over a span of two decades. Their objective was to hunt for signs of an IMBH by monitoring the movement of seven rapidly moving stars in the innermost area of the Omega Centauri globular star cluster.
Omega Centauri is an enormous globular cluster, comparable in mass to a small galaxy, housing around 10 million stars held together by gravity. These stars have offered convincing new proof of the existence of an Intermediate-Massive Black Hole affecting them gravitationally. So far, only a handful of other Intermediate-Massive Black Hole candidates have been identified.
The team created a comprehensive record of star movements by measuring velocities for 1.4 million stars identified in Hubble images of the cluster. Surprisingly, they found seven stars moving at such high speeds that they were expected to escape the cluster indefinitely. The most likely explanation is the presence of an Intermediate-Mass Black Hole (IMBH), a highly massive object exerting gravitational influence on these stars and keeping them close to the cluster's core. This IMBH is believed to have a mass of at least 8,200 times that of our Sun.
This discovery raises intriguing questions: How common are IMBHs? Could supermassive black holes evolve from IMBHs? And what processes lead to the formation of IMBHs? The study offers insights into the mysterious domain of intermediate-mass black holes and their importance in the cosmic interactions among celestial bodies.