We report on the detection of seven bursts from the periodically active , repeating fast radio burst ( FRB ) source FRB 180916.J0158+65 in the 300–400-MHz frequency range with the Green Bank Telescope ( GBT ) .
Emission in multiple bursts is visible down to the bottom of the GBT band , suggesting that the cutoff frequency ( if it exists ) for FRB emission is lower than 300 MHz .
Observations were conducted during predicted periods of activity of the source , and had simultaneous coverage with the Low Frequency Array ( LOFAR ) and the FRB backend on the Canadian Hydrogen Intensity Mapping Experiment ( CHIME ) telescope .
We find that one of the GBT-detected bursts has potentially associated emission in the CHIME band ( 400–800 MHz ) but we detect no bursts in the LOFAR band ( 110–190 MHz ) , placing a limit of \alpha > -1.0 on the spectral index of broadband emission from the source .
We also find that emission from the source is severely band-limited with burst bandwidths as low as \sim 40 MHz .
In addition , we place the strictest constraint on observable scattering of the source , < 1.7 ms , at 350 MHz , suggesting that the circumburst environment does not have strong scattering properties .
Additionally , knowing that the circumburst environment is optically thin to free-free absorption at 300 MHz , we find evidence against the association of a hyper-compact H ii region or a young supernova remnant ( age < 50 yr ) with the source .