For years, astronomers have been unable to agree on how early supermassive black holes formed so quickly after the Big Bang. Now, using data from Hubble and two additional space telescopes, researchers have revealed the most conclusive evidence thus far on how these interstellar phenomena were born.
Using computer models in combination with a new data analysis method from the NASA Chandra X-ray Observatory, the NASA/ESA Hubble Space Telescope and the NASA Spitzer Space Telescope, the team identified two objects that are believed to be the most likely candidates for black hole seeds. Each of the objects possesses an initial mass of approximately 100,000 times the sun, and they are observed less than a billion years following the Big Bang.
"Our discovery, if confirmed, would explain how these monster black holes were born," said Fabio Pacucci of Scuola Normale Superiore in Pisa, Italy and lead author of the study.
There are two main theories on supermassive black hole formation, with the first suggesting that seeds grow out of black holes with masses of approximately 10 to 100 times greater than our sun. These seeds then continue to grow through mergers with other small black holes. However, in order for the supermassive black holes already discovered in the young universe to fit this theory, they would have grown at unusually high rates.
The second theory, supported by the new findings, suggests that massive black hole seeds with masses 100,000 times that of our sun form through the collapse of massive gas clouds, which explains the quick growth of early supermassive black holes.
"There is a lot of controversy over which path these black holes take," said Andrea Ferrara of Scuola Normale Superiore and co-author of the study. "Our work suggests we are converging on one answer, where black holes start big and grow at the normal rate, rather than starting small and growing at a very fast rate."
"Black hole seeds are extremely hard to find and confirming their detection is very difficult," added Andrea Grazian from the National Institute for Astrophysics in Italy and co-author of the study. "However, we think our research has uncovered the two best candidates so far."
Although the two black hole seed candidates look promising, further research is needed in order to get a better grasp of their connection to the two supermassive black hole formation theories.
The findings were published online on March 28 in the Monthly Notices of the Royal Astronomical Society.
