NASA announced yesterday (May 24, 2016) that astrophysicists have taken a major step forward in understanding how supermassive black holes formed. Using data from three different telescopes, researchers have found the best evidence yet to suggest that supermassive black holes in the early universe were produced by the direct collapse of a massive gas cloud.
For years astronomers have debated how the earliest generation of supermassive black holes formed very quickly, relatively speaking, after the Big Bang. Now, an Italian team has identified two objects in the early universe that seem to be the origin of these early supermassive black holes. The two objects represent the most promising black hole seed candidates found so far.
Supermassive black holes contain millions or even billions of times the mass of the sun. In the modern universe they can be found in the center of nearly all large galaxies, including the Milky Way. The supermassive black hole in the center of the Milky Way has a mass of four million solar masses. The two black hole seed candidates would also be the progenitors of two of the modern supermassive black holes, say the researchers.
The group used computer models and applied a new analysis method to data from the NASA Chandra X-ray Observatory, the NASA/ESA Hubble Space Telescope, and the NASA Spitzer Space Telescope to find and identify the two objects. Both of these newly discovered black hole seed candidates are seen less than a billion years after the Big Bang and have an initial mass of about 100,000 times the sun.
Fabio Pacucci, of Scuola Normale Superiore in Pisa, Italy is lead author of the study. Pacucci said in a statement:
Our discovery, if confirmed, would explain how these monster black holes were born.
This new result helps to explain why we see supermassive black holes less than one billion years after the Big Bang.
There are two main theories to explain the formation of supermassive black holes in the early universe. One assumes that the seeds grow out of black holes with a mass about ten to a hundred times greater than our sun, as expected for the collapse of a massive star. The black hole seeds then grew through mergers with other small black holes and by pulling in gas from their surroundings. However, they would have to grow at an unusually high rate to reach the mass of supermassive black holes already discovered in the billion years young universe.
The new findings support another scenario where at least some very massive black hole seeds with 100,000 times the mass of the sun formed directly when a massive cloud of gas collapses. In this case the growth of the black holes would be jump started, and would proceed more quickly.
Andrea Ferrara also of Scuola Normale Superiore is a study co-author. Ferrara said:
There is a lot of controversy over which path these black holes take. 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.
Andrea Grazian, a study co-author from the National Institute for Astrophysics in Italy explained:
Black hole seeds are extremely hard to find and confirming their detection is very difficult. However, we think our research has uncovered the two best candidates so far.
Even though both black hole seed candidates match the theoretical predictions, further observations are needed to confirm their true nature. To fully distinguish between the two formation theories, it will also be necessary to find more candidates.
The study was published online in Monthly Notices of the Royal Astronomical Society on March 28, 2016.
Bottom line: Using data from three different telescopes, researchers have found the best evidence yet to suggest that supermassive black holes in the early universe were produced by the direct collapse of a massive gas cloud.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.