Dozen black holes found at galactic center
A dozen black holes may lie at the center of our galaxy, the Milky Way, researchers have said.
A new analysis provides support for a decades-old prediction that "supermassive" black holes at the centres of galaxies are surrounded by many smaller ones.
However, previous searches of the Milky Way's centre, where the nearest supermassive black hole is located, have found little evidence for this.
Details appear in the journal Nature, BBC News reports.
Charles Hailey from Columbia University in New York and colleagues used archival data from Nasa's Chandra X-ray telescope to come to their conclusions.
They report the discovery of a dozen inactive and low-mass "binary systems", in which a star orbits an unseen companion - the black hole.
The supermassive black hole at the centre of the Milky Way, known as Sagittarius A* (Sgr A*), is surrounded by a halo of gas and dust that provides the perfect breeding ground for the birth of massive stars. These stars live, die and could turn into black holes there.
In addition, black holes from outside the halo are believed to fall under the influence of Sgr A* as they lose their energy, causing them to be pulled into its vicinity, where they are held captive by its force.
Some of these bind - or "mate" - to passing stars, forming binary systems.
Previous attempts to detect this population of black holes have looked for the bright bursts of X-rays that are sometimes emitted by black hole binaries.