Mapping the Emission Location of the Crab Pulsar's Giant Pulses

The Crab pulsar has striking radio emission properties, with the two dominant pulse components -- the main pulse and the interpulse -- consisting entirely of giant pulses. The emission is scattered in both the Crab nebula and the interstellar medium, causing multi-path propagation and thus scintillation. We study the scintillation of the Crab's giant pulses using phased Westerbork data at 1668\,MHz. From correlations of the giant pulse spectra, we find that the main pulse and the interpulse are significantly offset in time and frequency. This suggests that they arise in physically distinct regions, which are, assuming the scattering takes place in the nebular filaments, separated by about a light cylinder radius (as projected on the sky). With further VLBI and multi-frequency data, it should be possible to measure both the distance to the scattering screens and the physical separation between the pulse components.