Cosmic-ray propagation in light of recent HAWC observations of Pulsar Wind Nebula

Abstract

Recent observations made with the High Altitude Water Cherenkov (HAWC) telescope of pulsar wind nebula (PWN) suggest that the diffusion in their vicinity is characterised with a lower diffusion constant than that predicted for propagation in the interstellar medium from observations of cosmic-ray (CR) fluxes at Earth. In this contribution, it is shown that models with the slow diffusion region localised about PWN can successfully explain the HAWC observations of the Geminga PWN and still retain consistency with other CR measurements. Parameter exploration shows that the size of the smaller diffusion zone has implications for the both the PWN emission at lower energies observable by the Fermi Large Area Telescope and the predicted positron flux at the Earth. Unless the Geminga PWN is unique, there are likely many small regions with slow diffusion throughout the Milky Way. The consequences for the propagation of CRs and the resulting interstellar emissions from across the Galaxy are discussed and explored.