Scientists have learned a bit more about a fast radio burst "afterglow." It turns out that the afterglow from a mysterious event may have actually belonged to a black hole.
Fast radio bursts (FRBs) are brief and yet powerful spurts of radio energy that last just a few milliseconds. The origin of FRBs, though, has long puzzled scientists. While researchers are able to see them in archival data, it's very hard to see one while they're in action.
In this latest study, the researchers investigated an FRB that actually occurred in real time. This event, called FRB 150418, is only the second FRB to be identified in real time. Radio observations showed a fading radio afterglow associated with the FRB. This afterglow was used to link the FRB to a host galaxy located about six billion light-years from Earth.
The next step was to then look a bit more closely at the host galaxy. In this case, the scientists found that there was a persistent radio source in the galaxy. If it had been an afterglow, it should have faded away rather than continuing as the scientists observed.
"What the other team saw was nothing unusual," said Edo Berger, one of the researchers involved in the new study. "The radio emission from this source goes up and down, but it never goes away. That means it can't be associated with the fast radio burst."
So what did the emission come from? It was likely from an active center of a galaxy. This center is powered by a supermassive black hole, similar to our own Milky Way galaxy. Twin jets shot out from the black hole, and can create a constant source of the radio waves that the researchers spotted.
"Right now the science of fast radio bursts is where we were with gamma-ray bursts 30 years ago," said Peter Williams, an astronomer from Harvard and one of the researchers. "We saw these things appearing and disappearing, but we didn't know what they were or what caused them. Now we have firm evidence for the origins of both short and long gamma-ray bursts. With more data and more luck, I expect we'll eventually solve the mystery of fast radio bursts too."
The findings have been accepted for publishing in Astrophysical Journal Letters.
