Fermi Gamma-ray Space Telescope

Fermi Large Area Telescope Detection of Extended of Gamma-Ray Emission from the Radio Galaxy Fornax A

J. D. Magill
W. McConville, ?. Stawarz, M. Georganopoulos, J. S. Perkins, on behalf of the Fermi-LAT Collaboration

Abstract:

Prior to the launch of Fermi in 2008, the radio galaxy Fornax A was identified as one of the few extragalactic objects that might be detected as extended above 100 MeV. However, even though it was detected with high confidence in the first 2 years of the mission, it was not determined to be an extended source. Recently, the Fermi-LAT collaboration developed a new event-level analysis called Pass 8 which yields a larger acceptance, a better angular and energy resolution, as well as smaller systematic uncertainties. The improvements provided with Pass 8 combined with a larger exposure means that the extension of Fornax A is significantly detected. Details of this measurement will be presented along with modeling of the emission above 100 MeV.