Ponente
Descripción
Models predict that the Sun can produce bright gamma-ray emission through two separate mechanisms. First, ambient cosmic-ray protons can undergo hadronic interactions with the solar atmosphere producing a bright flux across the solar disk. Second, cosmic-ray electrons can inverse-Compton scatter ambient sunlight to gamma-ray energies.
Observations by the Fermi-LAT and HAWC telescope have elucidated both components, and tracked their evolution across the solar cycle. We find that the inverse-Compton scattering emission from the Sun closely tracks theoretical expectations, verifying models of cosmic-ray transport in the inner heliosphere. The solar disk gamma-ray emission, on the other hand, has three surprising features. First, the gamma-ray emission extends to energies above 3 TeV, implying that Solar magnetic fields can redirect multi-TeV protons. Second, the morphology and spectrum of gamma-ray emission varies significantly over the solar cycle. Third, a significant “spectral-dip” appears between energies of 30-50 GeV. These observations are in significant tension with all current models of solar gamma-ray production.
