Particle Astrophysics is the study of how the smallest pieces of
matter in the universe interact on a cosmic scale. Scientists believe that by
studying particle interactions in space we can better understand why the universe
is the way it is. GLAST will probe novel astrophysical phenomena which could arise
as a result of new physics beyond our current standard model of particle interactions.
It is well established that, like most spiral galaxies, our own galaxy is immersed
in a dark halo that outweighs the luminous component by perhaps an order of magnitude.
The nature of this dark
matter is one of the biggest mysteries in particle physics
Huge amounts of dark
matter in a cluster of galaxies can cause
the light from a distant galaxy to appear as a halo due to gravitational lensing.
One of the leading candidates for the dark matter is a stable,
weakly interacting massive particle, or WIMP.
In the most plausible models, the mass of the WIMP falls between 10 GeV
and 300 GeV. If WIMPs exist in the galactic halo, then they could annihilate
and produce gamma
rays with photon
energies equal to the WIMP mass. These annihilation photons would be observable