For about a decade, scientists have been able to detect fast radio bursts (FRBs), elusive and powerful flashes that last only a few milliseconds. In that time, only 18 FRBs have been detected. Now, for the first time ever, researchers have isolated the source of several FRBs. They are coming from a dwarf galaxy that is billions of light years from Earth. The “most perplexing mystery in astronomy” – the source of FRBs – is now coming into focus.
Shami Chatterjee, an astrophysicist at Cornell University, says that by knowing the source of FRBs, scientists may be able to unlock clues as to what is causing them. He doesn’t think the cause is aliens, but doesn’t rule that out either. Instead, he believes that the FRBs could indicate interactions of a neutron star or an active galactic nucleus.
When the scientists found out that a particular FRB was bursting repeatedly, they ruled out the idea that the radio wave was being caused by two neutron stars colliding. The signal was more than just a radio flash or explosive crash; the repetition of FRB 121102 made them look deeper to find the cause.
The repetition also allowed them to focus their detection equipment at a single patch in the sky.
“If you go fishing in this spot in the sky, you might be more likely to get lucky than in other random spots in the sky,” Chatterjee says.
The research team was able to start using an interferometer in New Mexico, which consisted of 27 radio dishes called the Very Large Array. This provided them with greater resolution to detect the bursts. The equipment captured data at 200 frames per second at the selected spot in the sky.
“It was a pretty intensive observational and computational challenge,” Chatterjee commented.
After 50 hours of data recording, the research team found nothing of significance. That’s when they called on the Arecibo Observatory in Puerto Rico. The scientists there were able to capture nine radio images of the elusive bursts. The research teams all narrowed in on an even tinier patch in the sky. The source was revealing itself.
All signs pointed to the constellation Auriga, a dwarf galaxy that is 2.5 to 3 billion light years away. If their theory is correct, then the event causing the bursts had to have occurred billions of years ago. The scientists hypothesize that the cause could have been a newborn magnetar with a strong magnetic field spinning and emitting giant pulses. They say it could also be a magnetar colliding with a black hole, or it could have been an active galactic nucleus emitting blobs of vaporized plasma.
The study, published in the journal Nature, also questions whether all FRBs pulse repeatedly, or if some are singular bursts.