What Can GLAST Say about the Origin of Cosmic Rays in Other Galaxies?
Seth Digel, P. Sreekumar, Jonathan F. Ormes, Igor Moskalenko
Laboratory for High Energy Astrophysics, NASA,
Goddard Space Flight Center, Greenbelt, Maryland, USA
Roger Williamson
Hansen Experimental Physics Laboratory,
Stanford University, Palo Alto, California, USA
on behalf of the GLAST collaboration
Gamma rays in the band from 30 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 Magellenic
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 collision 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 (in the case of 30 Doradus in the LMC) is much greater.