Gamma rays in the band from 20 MeV to 300 GeV, used in combination with data
from radio and X-ray bands, provide a powerful tool for studying the origin of
cosmic rays in our sister galaxies Andromeda and the Magellanic Clouds.
Gamma-ray Large Area Space Telescope (GLAST) will spatially resolve these
galaxies and measure the spectrum and intensity of diffuse gamma radiation from
the collisions of cosmic rays with gas and dust in them. Observations of
Andromeda will give an external perspective on a spiral galaxy like the Milky
Way. Observations of the Magellanic Clouds will permit a study of cosmic rays
in dwarf irregular galaxies, where the confinement is certainly different and
the massive star formation rate is much greater.Comment: 4 pages including 6 figures; to appear in Proc. ACE-2000 Symp. "The
Acceleration and Transport of Energetic Particles Observed in the
Heliosphere" (Jan. 5-8, 2000, Indian Wells, CA), AIP Conf. Proc. More details
can be found at the LHEA GLAST page at
http://lhea-glast.gsfc.nasa.gov/pub/science/index.htm
