Speaker
Description
TeV gamma-ray halos are a new subclass of gamma-ray sources that could explain the positron excess measured by PAMELA, Fermi-LAT, and AMS-02. Geminga and Monogem are the first two gamma-ray halo candidates reported by the HAWC collaboration. The diffusion coefficient derived by the HAWC Collaboration, (4.5 +/- 1.2)x10^27 cm^2/s, differs more than 100 times from the average galactic value. We conducted a follow-up study using data from 2398 days of the HAWC gamma-ray observatory to model the diffuse emission of Geminga and Monogem using 3D template models of electron/positron inverse Compton gamma-ray emission. We used templates for diffusion coefficients between 10^25 - 10^27 cm^2/s and injection electron spectral indices between 0.0 - 2.2. We present preliminary diffusion coefficient values of 1.07x10^26 cm^2 and 1.47x10^26 cm^2/s for Geminga and Monogem. Furthermore, we estimate an electron/positron emission efficiency for Geminga and Monogem of 6.6% and 5.1%, respectively.
