HIGH TIME RESOLUTION INFRARED OBSERVATIONS OF THE CRAB-NEBULA PULSAR

The Crab Nebula pulsar (PSR 0531+21) was observed in the infrared in J (1.2 mum), H (1.6 mum), K (2.2 mum), and a 0.9-2.5 mum band on the Las Campanas 2.5 m and Mount Hopkins 1.2 m telescopes. A new detector was used, called the Solid State Photomultiplier (SSPM), which allowed measurements of unprecedented time resolution (approximately 20-50 mus) in these bands. The infrared pulse profiles are shown to be qualitatively similar to those at ultraviolet and optical wavelengths, but the main pulse widths and the pulse/interpulse separations increase from the ultraviolet to the infrared. These observations are consistent with the predictions of the outer magnetospheric gap models of high-energy pulsar emission. No evidence was found of the infrared ''shoulder'' of the main pulse or the excess infrared flux after the interpulse previously reported.