Since both direct and reflected photons are observed together, the reflecting source is typically a few percent of the overall flux. Consequently, contamination from the brighter spectral component handicaps our attempts to characterize and quantify reflection. The detection of an almost uncontaminated reflection spectrum is a rare event, but important in order to test and calibrate our understanding of X-ray reflection. The size, extent, spectrum and intensity of the pulsed X-ray source are also known. The characteristic light curve of X-rays reflected off the hemisphere of the companion star facing the pulsar is presented in the figure.
Maximum light occurs when the companion star is directly behind the pulsar.
Also below are spectral fits to three of the visits to Her X-1. The right hand panel presents the best fit model. The middle two panels are the corresponding fit and model for the post-eclipse visit at MJD 51372.15. At this time we cannot see the reflecting surface, which is over the limb of the companion star. The lower panels represent the visit at maximum flux, MJD 51372.90.