We report the detection of a single burst from the first-discovered repeating Fast Radio Burst source , FRB 121102 , with CHIME/FRB , which operates in the frequency band 400–800 MHz .
The detected burst occurred on 2018 November 19 and its emission extends down to at least 600 MHz , the lowest frequency detection of this source yet .
The burst , detected with a significance of 23.7 \sigma , has fluence 12 \pm 3 Jy ms and shows complex time and frequency morphology .
The 34 ms width of the burst is the largest seen for this object at any frequency .
We find evidence of sub-burst structure that drifts downward in frequency at a rate of -3.9 \pm 0.2 MHz ms ^ { -1 } .
Our best fit tentatively suggests a dispersion measure of 563.6 \pm 0.5 pc cm ^ { -3 } , which is { \approx } 1 % higher than previously measured values .
We set an upper limit on the scattering time at 500 MHz of 9.6 ms , which is consistent with expectations from the extrapolation from higher frequency data .
We have exposure to the position of FRB 121102 for a total of 11.3 hrs within the FWHM of the synthesized beams at 600 MHz from 2018 July 25 to 2019 February 25 .
We estimate on the basis of this single event an average burst rate for FRB 121102 of 0.1–10 per day in the 400–800 MHz band for a median fluence threshold of 7 Jy ms in the stated time interval .