CRAB PULSAR INFRARED FLUXES AND PULSE SHAPES

New JHKL, 1 ms time resolution, observations of the Crab pulsar strengthen the evidence for a 1/3 power law fall-off in the spectrum from the visible to the infrared. The shape of the infrared light curve is the same as the visible light curve, except that there is a depression of the peaks of the pulses, relative to the wings, of about 20 ± 10 per cent at H and K. If this depression is due to self-absorption, then the amount of self-absorption is 9 ± 5 per cent. If the sharp fall-off in flux towards shorter wavelengths in the visible continues into the ultraviolet, then the sharpness of the peak in the spectrum implies an excess of emitting particles of the corresponding energy. © 1982 Royal Astronomical Society.