<h2>Observations of the Crab Pulsar and
Nebula by the EGRET Telescope on the
Compton Gamma Ray Observatory</h2>
<h3>ApJ, 409, 697 (1993)</h3>
The Crab pulsar and nebula were observed three times in 1991 April
to June by the Energetic Gamma-Ray Experiment Telescope (EGRET)
on the Compton Gamma-Ray Observatory (CGRO): April 23 to May 7,
May 16 to 30, and June 8 to 15.  The results of analysis of the
gamma-ray emission in the energy range from 50 MeV to more than
10 GeV are reported.  The observed gamma-ray light curve exhibits
two peaks separated in phase by 0.40 +- 0.02, consistent with
previous observations.  The total pulsed emission from the Crab
pulsar is found to be well represented by a power-law spectrum
of the form
  (4.11 +- 0.16) x 10^(-9) (E/274 MeV)^(-2.15 +-0.04)
    photons / (cm^2 s MeV),
softer than the spectrum measured by COS B (Clear et al. 1987).
The evidence for pulsed emission above 5 GeV in the EGRET data is
not conclusive.  Unpulsed emission in the energy range 50 MeV
to 5 GeV was detected, with an indication of a hardening of the
unpulsed spectrum above about 1 GeV.  There was a significant
change in the light curve over the 2 months of these observations,
although the shape of the spectrum remained constant.

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