Fermi Gamma-ray Space Telescope

Astrophysical Models of the GeV Gamma-Ray Excess

T. Linden

Abstract:

Fermi-LAT observations over the last 6 years have discovered an excess in gamma-rays emanating from the Galactic Center of the Milky Way. In addition to models explaining this signal via the annihilation of particle dark matter, multiple detailed astrophysical models have been created in order to explain the spectral and morphological signatures of this excess. These include novel models of gas density and proton injection distributions in the inner galaxy, models of cosmic-ray outbursts from the dynamical center of the galaxy, and models positing new populations of gamma-ray pulsars in the inner kiloparsec of the Milky Way. In this talk, I will focus on the astrophysical models of the GeV excess, considering both their fit to gamma-ray and multi-wavelength data, as well as their feasibility based on the known physical characteristics of the GC region. I will conclude by pointing towards future observations which could significantly strengthen, or potentially rule out, both dark matter and astrophysical models of the GeV excess, bringing us closer to an accurate model for gamma-ray emission in the galactic center.