FRB 121102 Bursts Show Complex Time-Frequency Structure

Understand

FRB 121102 is the only known repeating fast radio burst source.

• Here we analyze a wide-frequency-range (1-8 GHz) sample of high-signal-to-noise, coherently dedispersed bursts detected using the Arecibo and Green Bank telescopes.
• These bursts reveal complex time-frequency structures that include sub-bursts with finite bandwidths.
• The frequency-dependent burst structure complicates the determination of a dispersion measure (DM); we argue that it is appropriate to use a DM metric that maximizes frequency-averaged pulse structure, as opposed to peak signal-to-noise, and find DM = 560.57 +/- 0.07 pc/cc at MJD 57644.