The Scattering Budget of Fast Radio Bursts Against Dispersion Measure

This paper computes the pulse-scattering budget of fast radio bursts from the empirical Galactic relation between scattering time and dispersion measure, evaluates it across the observed dispersion range and at the low-frequency edge of current surveys, and identifies the dispersion at which scattering alone would broaden a burst beyond easy detectability. The headline results are as follows. Predicted scattering time at dispersion measure 100: 0.0134 ms; Predicted scattering time at dispersion measure 300: 3.07 ms; Predicted scattering time at dispersion measure 600: 168 ms; Predicted scattering time at dispersion measure 1000: 4.29e+03 ms; Scattering time at 400 MHz for dispersion measure 600: 9.49e+03 ms; Dispersion at which the predicted scattering reaches 10 ms at 1 GHz: 372 pc cm-3. All values are computed from the stated assumptions and published inputs; the study is simulated and computed, not measured.