# Pulsars as candidates of LHAASO sources J2226+6057, J1908+0621 and J1825-1326: The leptonic origin

## TL;DR

This paper explores whether leptonic processes involving electrons accelerated by pulsars can explain the ultrahigh-energy gamma-ray emissions observed by LHAASO from sources J2226+6057, J1908+0621, and J1825-1326.

## Contribution

It introduces a leptonic model based on the Hertzian dipole pulsar model to explain the gamma-ray spectra, complementing previous hadronic models.

## Key findings

- Leptonic gamma-ray spectra roughly match LHAASO observations.
- Electrons can be accelerated to PeV energies by pulsar electromagnetic fields.
- The model supports leptonic origin as a plausible explanation for the observed gamma rays.

## Abstract

Recently, from 12 $\gamma$-ray Galactic sources, the LHAASO has detected ultrahigh-energy photons up to 1.4PeV. The $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, J1825-1326 and the suggested origin pulsars near the sources have been published. In our previous work, we studied the hadronic $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, J1825-1326 in terms of the Hertzian dipole model of pulsar. In this paper, we investigate the possibility of the leptonic origin of the $\gamma$-ray. We use the Hertzian dipole model to describe the pulsars around the sources. The electrons around the pulsars can be accelerated to PeV by the electromagnetic fields of pulsars. Under the assumption that the initial electrons are uniform distributed in a spherical shell between $10^{7}$ to $10^{9}$m around the pulsar, we obtain the energy distribution of electrons. The leptonic $\gamma$-ray spectra can be calculated through inverse Compton scattering processes. The leptonic $\gamma$-ray can roughly conform to the observation of LHAASO.