  Quantitative modeling of the spectro-spatial distributions of energetic
electrons and protons in galactic halos is needed in order to determine their
interactions with the local plasma and radiation fields, and also to estimate
their residual spectral densities in intracluster and intergalactic
environments. We develop a semi-analytic approach for calculating the particle
distributions in the halo based on a detailed diffusion model for particle
propagation from acceleration sites and interactions in the galactic disk.
Important overall normalization of our models is based on results from detailed
modeling in the Galactic disk with the GALPROP code. This provides the
essential input for determining particle distributions in the outer disk, which
are used as source terms for calculating the distributions in the extensive
halo for a range of values of key parameters affecting energy losses and
propagation mode. Our modeling approach is applied to the two edge-on
star-forming galaxies NGC 4631 and NGC 4666, for which recent mapping of radio
emission in the inner halo provides the required overall normalization. We
predict the levels and spatial profiles of radio, X-ray, and gamma-ray emission
in the halos of these galaxies. Our quantitative modeling enables us to
estimate the total calorimetric efficiencies of electrons and protons in
star-forming galaxies, and to predict their residual spectral distributions in
the outer halo and intergalactic space.
