Hadronic Re-Acceleration at the Crab Pulsar Wind Termination Shock as a Source of PeV Gamma-Rays

Abstract

Recent results from LHAASO and Tibet AS$\gamma$ suggest that the Crab Nebula's gamma-ray spectrum extends to the PeV energy range, however the production mechanisms of this highest energy emission remain unclear. It has been postulated that a secondary component of hadronic emission could explain the highest energy gamma-ray flux points, however the origin and acceleration mechanism for this hadronic population has yet to be explained. We postulate one scenario in which hadrons diffuse over time into the Crab pulsar wind nebula from the surrounding supernova ejecta, and are subsequently re-accelerated by the pulsar wind termination shock. We present results of direct particle transport simulations (including radial evolution) to determine if this scenario is viable over the lifetime of the Crab system.

7 pages, 2 figures. From proceedings of the 38th International Cosmic Ray Conference (ICRC2023)

References in corpus (3)

• A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars
• Rayleigh-Taylor instability in Magnetohydrodynamic Simulations of the Crab Nebula
• Modeling the broadest spectral band of the Crab nebula and constraining the ions acceleration efficiency