Are there multiple populations of Fast Radio Bursts?

Understand

The repeating FRB 121102 (the "repeater") shows {repetitive bursting activities} and was localized in a host galaxy at $z=0.193$.

• On the other hand, despite dozens of hours of telescope time spent on follow-up observations, no other FRBs have been observed to repeat.
• Yet, it has been speculated that the repeater is the prototype of FRBs, and that other FRBs should show similar repeating patterns.
• Using the published data, we compare the repeater with other FRBs in the observed time interval ($\Delta t$) - flux ratio ($S_i / S_{i+1}$) plane.