The Spatial Morphology of the Secondary Emission in the Galactic Center
  Gamma-Ray Excess
  Excess GeV gamma rays from the Galactic Center (GC) have been measured with
the Fermi Large Area Telescope (LAT). The presence of the GC excess (GCE)
appears to be robust with respect to changes in the diffuse galactic background
modeling. The three main proposals for the GCE are an unresolved population of
millisecond pulsars (MSPs), outbursts of cosmic rays from the GC region, and
self-annihilating dark matter (DM). The injection of secondary electrons and
positrons into the interstellar medium (ISM) by an unresolved population of
MSPs or DM annihilations can lead to observable gamma-ray emission via inverse
Compton scattering or bremsstrahlung. Here we investigate how to determine
whether secondaries are important in a model for the GCE. We develop a method
of testing model fit which accounts for the different spatial morphologies of
the secondary emission. We examine several models which give secondary emission
and illustrate a case where a broadband analysis is not sufficient to determine
the need for secondary emission.
