Scintillation Bandwidth Scaling for Dispersed Radio Sources

This paper computes how the diffractive scintillation bandwidth of a dispersed radio source scales with observing frequency and dispersion measure, evaluates the scaling at the parameters of current fast radio burst surveys, and determines where the pattern becomes finer than the spectral resolution of the instruments recording it. The headline results are as follows. Scintillation bandwidth at 1 GHz for dispersion measure 100: 12 MHz; Scintillation bandwidth at 1 GHz for dispersion measure 500: 0.348 MHz; Scintillation bandwidth at 600 MHz for dispersion measure 500: 0.0368 MHz; Scintillation bandwidth at 1.4 GHz for dispersion measure 50: 242 MHz; Scintillation timescale at 1 GHz for dispersion measure 100: 10 min; Frequency at which the bandwidth equals a 400 MHz observing band for dispersion measure 500: 4.96 GHz. All values are computed from the stated assumptions and published inputs; the study is simulated and computed, not measured.