High speed phase-resolved 2-d ubv photometry of the crab pulsar

We report a phase-resolved photometric and morphological analysis of UBV data of the Crab pulsar obtained with the 2-d TRIFFID high speed optical pho- tometer mounted on the Russian 6m telescope. By be- ing able to accurately isolate the pulsar from the nebular background at an unprecedented temporal resolution (1 µs), the various light curve components were accurately fluxed via phase-resolved photometry. Within the UBV range, our datasets are consistent with the existing trends reported elsewhere in the literature. In terms of flux and phase duration, both the peak Full Width Half Maxima and Half Width Half Maxima decrease as a function of photon energy. This is similarly the case for the flux asso- ciated with the bridge of emission. Power-law fits to the various light curve components are as follows; � = 0.07 ± 0.19 (peak 1) , � = -0.06 ± 0.19 (peak 2) and � = -0.44 ± 0.19 (bridge) - the uncertainty here being dominated by the integrated CCD photometry used to independently reference the TRIFFID data. Temporally, the main peaks are coincident to � 10 µs although an accurate phase lag with respect to the radio main peak is compromised by ra- dio timing uncertainties. The plateau on the Crab's main peak was definitively determined to be � 55 µs 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 evi- dence of anything akin to the giant pulses noted in the radio. Finally, there is no evidence to support the exis- tence of a reported 60 second modulation suggested to be as a consequence of free precession.