Using data from NASA's Chandra X-ray Observatory, researchers have discovered a massive swarm of black holes near the center of Milky Way galaxy. The newly identified black holes are star-mass black holes formed by the gravitational collapse of extremely massive stars, typically weighing 5 to 30 times the mass of the Sun. These black holes are three light years away from Sagittarius A *, the supermassive black holes in the center of the galaxy. This is a relatively short distance in cosmic terms.
Scientists have long assumed that the Milky Way at its center harbors a large population of stellar black holes because of the halo of gas and dust around Sagittarius A *. This region of gas and dust could serve as a perfect breeding ground for the birth of massive stars that can live, die and turn into black holes. Extensive research has been done over the years on these black holes, but no population has been discovered so far. The recent analysis of Chandra data is the first evidence of such a black hole discovery.
Black holes themselves are invisible objects, so we can not see them directly. However, a black hole or neutron star trapped in close orbit with another star continually pulls material away from its stellar companion, which falls onto a disk and produces momentary X-rays. The bright burst of X-rays that occurs in black-bin binaries is sometimes detected by observatories like Chandra. When researchers used Chandra data to search for X-ray binaries that contained black holes near Sgr A *, they found fourteen X-ray binaries within about three light years of the supermassive black hole. Based on the characteristic bursts, the researchers concluded that the majority of these dozen X-ray binaries will likely contain black holes instead of neutron stars. Around Sgr A * must have 300 to 1
"The existence of a" density hump "- a localized increase in the number – of stellar black holes near a supermassive black hole is a fundamental prediction of galactic stellar dynamics – the best place to do such a spike to discover is in the Galactic Center, where the next supermassive black hole, Sagittarius A *, resides, "the authors wrote in the study.
"The properties of these X-ray binaries, especially their spatial distribution and luminosity function, suggest the existence of hundreds of binary systems in the central parsec of the galaxy and many other isolated black holes."