High-Time-Resolution Optical Observations of the Crab Pulsar

Although optical pulsar studies are currently limited a few favoured objects, the observation of pulsars at optical wavelengths provides an opportunity to derive a number of important pulsar characteristics. These parameters will be vital for a comprehensive model of pulsar emission mechanisms. The exploitation of the data available through optical pulsar studies requires that high-time-resolution instruments suitable for the optical domain, and for faint pulsar targets, are developed and thoroughly tested. Observations of the Crab pulsar with the high-time-resolution photon-tagging photometer IquEYE show an optical-radio delay of ˜178 μs. In conjunction with simultaneous Jodrell Bank radio observations, a correlation between giant radio pulses and enhanced optical pulses was detected for this pulsar, which is possible evidence for the reprocessing of radio photons. Comparison with optical linear polarisation measurements indicate a shift between linear and circular polarisation at the radio precursor phase.