High speed phase-resolved 2-d UBV photometry of the Crab pulsar

We report a phase-resolved photometric and morphological analysis of UBV da ta of the Crab pulsar obtained with the 2-d TRIFFID high speed optical phot ometer mounted on the Russian 6m telescope. By being able to accurately iso late the pulsar from the nebular background at an unprecedented temporal re solution (1 mus), the various light curve components were accurately fluxed via phase-resolved photometry. Within the UBV range, our datasets are cons istent with the existing trends reported elsewhere in the literature In ter ms of flux and phase duration, both the peak Full Width Half Maxima and Hal f Width Half Maxima decrease as a function of photon energy. This is simila rly the case for the flux associated with the bridge of emission. Power-law fits to the various light curve components are as follows; alpha = 0.07 +/ - 0.19 (peak 1), alpha = -0.06 +/- 0.19 (peak 2) and alpha = -0.44 +/- 0.19 (bridge) - the uncertainty here being dominated by the integrated CCD phot ometry used to independently reference the TRIFFID data. Temporally, the ma in peaks are coincident to less than or equal to 10 mus although an accurat e phase lag with respect to the radio main peak is compromised by radio tim ing uncertainties. The plateau on the Crab's main peak was definitively det ermined to be less than or equal to 55 mus in extent and may decrease as a function of photon energy. There is no evidence for non-stochastic activity over the light curves or within various phase regions, nor is there eviden ce of anything akin to the giant pulses noted in the radio. Finally, there is no evidence to support the existence of a reported 60 second modulation suggested to be as a consequence of free precession.