Repeating radio signals from a mysterious source in a dwarf galaxy 3 billion light-years away have been detected by astronomers.
Using the Green Bank Telescope in West Virginia, scientists with the Breakthrough Listen initiative—a massive project dedicated to finding signs of intelligent alien life—recorded 15 repeating fast radio bursts (FRBs) on August 26.
The FRBs only last a few milliseconds, appearing to be coming from deep space. Because FRBs have an extremely short duration, and because scientists usually find them in data only after the event has taken place, pinpointing their origin has not been possible.
Almost two dozen FRBs have been recorded. Most often, they are one-off events, but in 2016 scientists announced in the journal Nature that they had found a repeating radio signal—FRB 121102. By monitoring and tracking this repeating burst, they were able to trace it back to a dwarf galaxy 3 billion light-years away. Still, the source remained elusive. Nothing that we know of in that region of space could be producing these signals.
Now the Breakthrough Listen team has detected 15 more busts coming from FRB 121102. Vishal Gajjar, a postdoctoral researcher at the University of California, Berkeley, where Breakthrough Listen is based, observed the new bursts during a monitoring effort run. He and his colleagues collected 400 terabytes of data over the 4 to 8 GHz frequency band, or C-band, which is mostly used for satellite communications.
Initial results indicate that FRBs emit at higher frequencies than previously observed. This discovery that should help scientists determine the source producing the bursts.
Several explanations for FRBs have been suggested.
Despite widespread speculation, the possibility of the signals coming from an advanced alien civilization has been largely ruled out.