Chromatic periodic activity down to 120 MHz in a Fast Radio Burst

Understand

Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, millisecond-duration bursts.

• FRBs have thus far been detected between 300 MHz and 8 GHz, but lower-frequency emission has remained elusive.
• A subset of FRBs is known to repeat, and one of those sources, FRB 20180916B, does so with a 16.3 day activity period.
• Using simultaneous Apertif and LOFAR data, we show that FRB 20180916B emits down to 120 MHz, and that its activity window is both narrower and earlier at higher frequencies.