NASA Observes a Disappearing Black Hole for the First Time, Might be Caused by Passing Star
When NASA researchers observe a black hole, they normally view it at the center of a far-off galaxy, slowly consuming a disk of gas that swirls around it like water circling a drain. However, two years ago, astronomers were perplexed as X-rays from the black hole corona in a galaxy known as 1ES 1927+654 disappeared completely, fading by a factor of 10,000 in about 40 days. Even stranger, it almost immediately began to rebound, and around 100 days later, had become 20-times brighter than before the event.
When the X-rays from the black hole’s corona disappeared, NASA’s Neutron star Interior Composition Explorer (NICER) and Neil Gehrels Swift Observatory discovered lower-energy X-rays from the system so that, combined, these observatories provided a continuous stream of information throughout the event. They assume that a wayward star is the most likely culprit, and that the black hole shredded it, inadvertently sending debris at its own feeding disk.
We just don’t normally see variations like this in accreting black holes. It was so strange that at first we thought maybe there was something wrong with the data. When we saw it was real, it was very exciting. But we also had no idea what we were dealing with; no one we talked to had seen anything like this,” said Claudio Ricci, an assistant professor at Diego Portales University in Santiago, Chile, and lead author of the study.