GALACTIC GAMMA-RAYS FROM THE INVERSE COMPTON PROCESS

The extent to which gamma rays from inverse Compton collisions contrib ute to the measured gamma-ray Bur in the satellite energy band (30-400 0 MeV) is examined. The problems inherent in the estimate are discusse d, not least the uncertainty in the scale height of cosmic-ray electro ns and in the extent to which the local cosmic-ray intensity is spatia lly variable. Most of the paper refers to the derivation of the effect ive IC contribution, effective in the sense of being such as to accoun t for the bulk of the large-scale gamma-ray intensity variations. It i s found by demanding that the cosmic-ray intensity is constant over th e region of space within similar to 1 kpc of the Sun. In this case, th e ic contribution to the total Galactic diffuse intensity is 32 +/- 10 % for the Galactic latitude range 10-20 degrees, increasing to 44 +/- 17% at the Galactic poles. The corresponding scale height of the elect ron component is z1/2 = (2.5 +/- 1) kpc. There are still CR intensity changes needed locally but these are on comparatively small scales; if later work should show that the CR intensity changes are, in fact, la rger then the IC contribution will have to be reduced.