PHASE DISTRIBUTION OF THE 0.44 MEV FEATURE IN THE CRAB PULSAR SPECTRUM

On 1990 July 9, the balloon-borne experiment FIGARO II (0.15 - 4 MeV) observed the Crab region. The light-curve of PSR 0531+212 shows, in addition to the well-known two-peak structures, evidence for extra structures at absolute radio phases 0.1, 0.3, and 0.45 around the energy 0.44 MeV. The phase-resolved spectroscopy confirms that an excess, compatible with a line-like feature, is present at these phase positions.