HAWC Observations on Two Nearby Pulsar Wind Nebulae Constrain the Origin of Local Positrons
Nearby electron and positron accelerators, especially Pulsar Wind Nebulae, have been proposed as potential origins of the local multi-GeV positron excess. The HAWC Gamma-Ray Observatory has reported very extended TeV gamma-ray emission around two nearby middle-aged pulsars Geminga and B0656+14, suggesting ultra-relativistic electrons and positrons accelerated in our backyard. The gamma-ray profiles up to tens of parsecs around these two pulsars provide a direct constraint on the diffusion of electrons and positrons in the interstellar medium. We will present the spatial and spectral studies on these two TeV gamma-ray sources and the derived positron contribution at Earth.