Photometric Studies of Cygnus X-1 from 322-473 KEV with the Solar Maximum Mission

We present results from three years of observations from Cygnus X-1 and the Crab Nebula using the Gamma Ray Spectrometer onboard the Solar Maximum Mission satellite. We show that using a neural network based background model, it is possible to predict the terrestrial component of the gamma-ray background to a <1% level. We also show that the flux from the Crab is steady over a three year period at level of 0.024 +/- 0.002 gamma cm^ {-2} s^{-1} MeV^ {-1}. Similarly, the flux from Cygnus X-1 was consistent with the flux measured in 1979 with HEAO-3 and in 1991 with BATSE. We measured a flux of 0.013 +/- 0.003 gamma cm^{-2} s^{-1 } MeV^{-1}. We discuss the electron lifetimes within the Crab Nebula and limits on temperature variations from the Cygnus X-1 accretion disk.