The GALPROP model for cosmic-ray (CR) propagation produces explicit
predictions for the angular distribution of Galactic diffuse gamma rays. We
compare our current models with EGRET spectra for various regions of the sky.
This allows a critical test of alternative hypotheses for the observed GeV
excess. We show that a population of hard-spectrum gamma-ray sources cannot be
solely responsible for the excess since it also appears at high latitudes; on
the other hand a hard CR electron spectrum model cannot explain the gamma-ray
excess in the inner Galaxy. Hence some combination of these explanations is
suggested.Comment: 4 pages, 12 ps-figures, tsukuba.sty, to appear in the Proc. 28th
International Cosmic Ray Conference (Tsukuba, Japan 2003). More details can
be found at http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm