Extended Data Fig. 1: FRB 20221022A burst dynamic spectrum (panel c), profile (panel b), spectrum (panel d) and modulation index (panel a).
From: Magnetospheric origin of a fast radio burst constrained using scintillation
The burst is dedispersed to a dispersion measure10 of 116.837 pc cm−3 and is plotted with time and frequency resolution 40.96 μs and 6.2 MHz, respectively. The rise and decay time are highlighted using the shaded red regions in b. Both the on-burst time-averaged spectrum and off-burst spectrum are shown in d. For each 163.84 μs time bin, we compute the ACF (equation (1)) across frequency (ACF is computed for spectra with a frequency resolution of 24 kHz), and measure the modulation index as the height of the Lorentzian fit to the ACF around zero lag. We only plot modulation indices for 163.84 μs time bins that have a S/N > 8 (a). The mean of the measured time resolved modulation indices for the 128 kHz scintillation scale is shown with the red line in a, and is measured to be \(\bar{m}=0.76\pm 0.06\), consistent with the frequency-resolved modulation index measured for this scintillation scale.
