The Spatial Morphology of the Secondary Emission in the Galactic Center Gamma-Ray Excess

Understand

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.