## Doctoral Dissertations

Spring 1996

Dissertation

Physics

#### Degree Name

Doctor of Philosophy

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 $\pm$ 0.002 $\gamma$ cm$\rm\sp{-2}\ s\sp{-1}\ MeV\sp{-1}$. 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 $\pm$ 0.003 $\gamma\rm\ cm\sp{-2}\ s\sp{-1}\ MeV\sp{-1}$. We discuss the electron lifetimes within the Crab Nebula and limits on temperature variations from the Cygnus X-1 accretion disk.