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

TL;DR

This paper explores the potential of nearby pulsars as sources of ultrahigh-energy gamma rays observed by LHAASO, proposing a hadronic acceleration mechanism that matches observed spectra.

Contribution

It introduces a model where pulsars accelerate protons to PeV energies, explaining the gamma-ray spectra of specific LHAASO sources for the first time.

Findings

Protons near pulsars can reach PeV energies rapidly.

Hadronic gamma-ray spectra from pulsars align with LHAASO observations.

Pulsars are viable PeVatrons for observed ultrahigh-energy gamma rays.

Abstract

The LHAASO Collaboration has observed ultrahigh-energy photons up to $1.4$PeV from $12$ $\gamma$-ray Galactic sources. In particular, the $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, 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 uniform 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 $\gamma$-ray spectra of the suggested origin pulsars are in good agreement with the LHAASO observed $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, J1825-1326.