In a groundbreaking new analysis of data from the Chandra X-ray Observatory, astronomers have uncovered a hidden population of supermassive black holes. These mysterious and controversial phenomena in the universe can accumulate billions of suns within them and were previously undiscovered.
The team, led by Dong-Woo Kim of the Center for Astrophysics, combined data from the Chandra Source Catalogue and optical data from the Sloan Digital Sky Survey (SDSS) to identify hundreds of black holes that had previously been hidden. These black holes are in galaxies that were not previously identified as containing quasars, extremely bright objects with rapidly growing supermassive black holes.
A black hole is formed from the death of a star with such a high gravitational field that the matter is squeezed into the small space under it, trapping the light of the dead star. The gravity is so strong due to the matter being squeezed into a tiny space, making it impossible for light to escape, making black holes invisible to the human eye.
“Our research has uncovered a missing population and helped us understand how they are behaving,” said Kim in a statement. The team systematically combed through data from the Chandra Source Catalogue and identified 817 XBONG candidates, more than ten times the number known before Chandra was in operation. Nasa stated that Chandra’s sharp images, matching the quality of those from SDSS, and a large amount of data in the Chandra Source Catalog made it possible to detect this many XBONG candidates.
The team studied X-rays as material swirling around a black hole is superheated to millions of degrees and glows strongly in X-ray wavelengths. After studying the number of X-rays detected at different energies for each source, the team concluded that about half the XBONG candidates involve X-ray sources that are buried under thick gas.
“These results show how powerful it is to compare X-ray and optical data mines. The Chandra Source Catalog is a growing treasure that will help astronomers make discoveries for years to come,” said co-author Amanda Malnati.
A graduate student at the University of British Columbia, Alyssa Cassity, said that it’s not every day that you can say you discovered a black hole and it’s very exciting to realize that we have discovered hundreds of them.