Scientists have spotted the oldest supermassive black hole ever seen in the universe, giving us a glimpse back into the dawn of the cosmos.
Led by the Carnegie Institution for Science in California, the team used a number of telescopes including NASA’s Wide-field Infrared Survey Explorer (WISE) in orbit to make the discovery. The findings are published in Nature.
This black hole is surrounded by a superheated region of dust and gas known as a quasar. It's believed to originate just 690 million years after the Big Bang, with the light taking 13 billion years to reach us. Its age raises new questions on how such massive black holes could form so early in the universe.
The black hole inside this quasar, called J1342+0928, is thought to be about 800 million times the mass of the Sun. That’s far in excess of many of the supermassive black holes we see residing at the center of galaxies today (ours is 4 million solar masses).
What's more, its age means it must have grown incredibly quickly. It may have been an "early bloomer", eventually settling down into a more typical supermassive black hole inside a galaxy.
“It is very challenging to collect all that mass in a single point in such a short time,” Eduardo Bañados, the study’s lead author, told IFLScience.
“So theorists are thinking really hard how this process could happen as well of thinking of different alternatives. Finding more supermassive black holes at earlier times will constrain even further black hole growth models.”
At the time this distant quasar existed, the first galaxies of the universe were just starting to form. Their radiation ionized the interstellar gas, changing the universe from neutral to ionized. This is known as the epoch of reionization, when the first stars started to shine.
This quasar is seen surrounded by neutral hydrogen, which suggests it is indeed from this epoch. Its distance was determined by measuring its redshift, which is the stretching of its light due to the expansion of the universe. The higher it is, the greater the distance – in this case, its redshift was 7.54.
Only 20 to 100 other quasars of this brightness and distance are thought to be visible from Earth, making this a major discovery. It allows us to peer into the early universe, when it was just 5 percent its current age, and see what conditions were like long ago.
“This great distance makes such objects extremely faint when viewed from Earth,” study co-author Xiaohui Fan, from the University of Arizona’s Steward Observator, said in the statement. “Early quasars are also very rare on the sky. Only one quasar was known to exist at a redshift greater than seven before now, despite extensive searching.”
Now, astronomers are hoping that a host of new telescopes coming online soon, such as the Giant Magellan Telescope (GMT) in Chile, due for completion in 2025, will unearth more of these distant objects.
