Study Finds Tens of Thousands of Black Holes in Milky Way’s Center

Astrophysicists have discovered 12 black hole-low mass binaries orbiting Sgr A* at the center of the Milky Way galaxy. (Image: via   pixabay  /  CC0 1.0)
Astrophysicists have discovered 12 black hole-low mass binaries orbiting Sgr A* at the center of the Milky Way galaxy. (Image: via pixabay / CC0 1.0)

A Columbia University-led team of astrophysicists has discovered a dozen black holes gathered around Sagittarius A* (Sgr A*), the supermassive black hole in the center of the Milky Way Galaxy. The finding, which has been published in Natureis the first to support a decades-old prediction, opening up myriad opportunities to better understand the universe.

Astrophysicist Chuck Hailey, co-director of the Columbia Astrophysics Lab and lead author on the study, said in a statement:

For more than two decades, researchers have searched unsuccessfully for evidence to support a theory that thousands of black holes surround supermassive black holes (SMBHs) at the center of large galaxies, Hailey explained:

He added that extensive fruitless searches have been made for black holes around Sgr A*, the closest SMBH to Earth and therefore the easiest to study.

He explained that Sgr A* is surrounded by a halo of gas and dust that provides the perfect breeding ground for the birth of massive stars, which live, die, and could turn into black holes there.

Additionally, black holes from outside the halo are believed to fall under the influence of the SMBH as they lose their energy, causing them to be pulled into the vicinity of the SMBH, where they are held captive by its force.

While most of the trapped black holes remain isolated, some capture and bind to a passing star, forming a stellar binary. Researchers believe there is a heavy concentration of these isolated and mated black holes in the Galactic Center, forming a density cusp that gets more crowded as distance to the SMBH decreases.

In the past, failed attempts to find evidence of such a cusp have focused on looking for the bright burst of X-ray glow that sometimes occurs in black hole binaries, Hailey said:

To detect black hole binaries then, Hailey and his colleagues realized they would need to look for the fainter, but steadier X-rays emitted when the binaries are in an inactive state, Hailey explained that:

Hailey and colleagues turned to archival data from the Chandra X-ray Observatory to test their technique. They searched for X-ray signatures of black hole-low mass binaries in their inactive state and were able to find 12 within three light years of Sgr A*.

The researchers then analyzed the properties and spatial distribution of the identified binary systems and extrapolated from their observations that there must be anywhere from 300 to 500 black hole low-mass binaries and about 10,000 isolated black holes in the area surrounding Sgr A*.

Provided by: Columbia University [Note: Materials may be edited for content and length.]

Like this article? Subscribe to our weekly email for more!     

The Mystery of China’s Floating City