Pulsars as candidates of LHAASO sources J2226+6057, J1908+0621, and J1825−1326

Abstract

ABSTRACT The Large High Altitude Air Shower Observatory (LHAASO) Collaboration has observed ultrahigh-energy photons up to 1.4 PeV from 12 $\gamma$-ray Galactic sources. In particular, the γ-ray spectra of the sources J2226+6057, J1908+0621, and J1825−1326 have been published. We investigate the possibility of suggested origin pulsars near the sources as the PeVatrons. The pulsar is described by a rotating magnetic dipole. Assuming protons are uniformly distributed out of the light cylinders, we obtain the Lorentz distribution of proton energy spectrum. It is found that the protons around pulsar could be accelerated to PeV at short times. The hadronic γ-ray spectra of the suggested origin pulsars are in good agreement with the LHAASO observed γ-ray spectra of the sources J2226+6057, J1908+0621, and J1825−1326.