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Observations with Ginga have allowed an unprecedented view of the recurrent systematic pulse shape changes associated with the 35-day cycle of Her X-1, a phenomena currently unique to this accretion-powered X-ray pulsar. We present observations of the pulse shape evolution and a phenomenological model for the evolution based upon an occultation of the pulse emitting region by the tilted, inner edge of a precessing accretion disk. A composite pencil and fan beam is proposed for the pulsar beam but the observed evolution pattern requires the fan beam to be focused around the neutron star and beamed in the antipodal direction. The spectral hardness of the pencil beam component suggests an origin at the magnetic polar cap, with the relatively softer fan beam emission produced by backscattering from within the accretion column.
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