Kinematics of Crab Giant Pulses

Understand

The Crab Pulsar's radio emission is unusual, consisting predominantly of giant pulses, with durations of about a micro-second but structure down to the nano-second level, and brightness temperatures of up to $10^{37}\,$K.

• It is unclear how giant pulses are produced, but they likely originate near the pulsar's light cylinder, where corotating plasma approaches the speed of light.
• We report observations in the 400-800 MHz frequency band, where the pulses are broadened by scattering in the surrounding Crab nebula.
• We find that some pulse frequency spectra show strong bands, which vary during the scattering tail, in one case showing a smooth upward drift.