In 2018, astronomers were alerted by a strange phenomenon detected by the All-Sky Automated Survey for Super-Novae (ASSASN). A supermassive black hole, which belonged in the class called Active Galactic Nuclei (AGN), shone 40 times brighter than usual. When they were alerted by the ASSASN, the astronomers quickly pointed their telescopes toward the AGN. Here, things got really mind-boggling.
While observing the AGN in X-ray, optical and ultraviolet light, scientists watched in surprise as the light faded, its brightness dropping by a factor of 10,000 until it was no longer detectable at all. Scientists have never seen a burnout that drastic happen so quickly.
But that wasn’t the end. Within a few months the light had been rekindled, firing back up almost to its original luminosity, which has also never been seen before.
“This seems to be the first time we’ve ever seen a corona first of all disappear, but then also rebuild itself, and we’re watching this in real-time,” says Kara. “This will be really important to understanding how a black hole’s corona is heated and powered in the first place.”
While the team may have some speculations on the event, they still couldn’t explain the phenomenon fully, which makes this all the more mysterious.
This just goes to show how much we still don’t know about our universe.
(Image Credit: NASA/JPL-Caltech/ New Atlas)