The 2009 Fermi Symposium

Deciphering the Gamma-ray Background: Starforming Galaxies, AGN, and the Search for Dark Matter in the GeV Band

Vasiliki Pavlidou

Abstract:

The Fermi Gamma-ray Space Telescope promises a decade of excitement and discovery in the GeV Band. While Fermi represents a dramatic improvement in instrumental capabilities for point source observations in GeV gammas (as well as a much deeper understanding of the Galactic interstellar GeV emission) compared to its predecessors, much of GeV science will still be encoded in the unresolved, isotropic diffuse background, due to restrictions in point source sensitivity and angular resolution inherent in GeV energies. I will discuss the two guaranteed astrophysical contributions to the isotropic diffuse gamma-ray background (starforming galaxies and gamma-ray-loud AGN), and how diffuse GeV observations can be used to further our understanding of the high energy properties of these familiar populations. Finally, I will describe some promising techniques for disentangling unresolved diffuse emission from different source classes and circumventing the difficulties presented by astrophysical backgrounds to hopefully uncover a dark matter annihilation signal which may be hiding among the diffuse GeV photons.