Black holes found in Milky Way galaxy

There are only about five dozen known black holes in the entire galaxy 100,000 light years wide.

Hyderabad: The decade-old prediction that the centre of the Milky Way galaxy is filled with black holes was confirmed by astrophysicists. They discovered a dozen black holes gathered around Sagittarius A*(sgr A*) the super massive black hole in the centre of the Milky Way galaxy. These findings are significantly going to advance gravitational wave research because knowing the number of black holes can help in better predicting on how many gravitational wave events might be associated with them.

All the information astrophysicists needed is at the centre of the galaxy. This discovery by a Columbia University-led team of astrophysicists opened up myriad opportunities to better understand the universe. A black hole is a region of space time exhibiting strong gravitational effects that nothing, not even particles and electromagnetic radiation such as light, can escape from inside.

Researchers had made unsuccessful attempts in finding evidence for supporting a theory that thousands of black holes surrounded supermassive black holes (SMBHs) at the centre of large galaxies. Following the observations, researchers concluded that there must be at least 10,000 isolated black holes in the area surrounding Sgr A*, the closest blackhole to earth.

“Everything you’d ever want to learn about the way big black holes interact with little black holes, you can learn by studying this distribution,” said astrophysicist Chuck Hailey, co-director of the Columbia Astrophysics Lab and lead author on the study. There are only about five dozen known black holes in the entire galaxy — 100,000 light years wide — and there were supposed to be 10,000 to 20,000 of these things in a region just six light years wide that no one had been able to find.

Sgr A* is surrounded by a halo of gas and dust where in massive stars could take birth, live, die and could turn into black holes. Other black holes outside this halo are assumed to fall under the influence of the SMBH. This was because they would lose their energy which caused them to be pulled into the vicinity of the SMBH to be held captive by its force.

These trapped black holes often remain isolated; some captured and bound to a passing star, forming a stellar binary. “If we could find black holes that are coupled with low mass stars and we know what fraction of black holes will mate with low mass stars, we could scientifically infer the population of isolated black holes out there,” said Mr Hailey.

( Source : Deccan Chronicle. )
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