Investigating the [formula omitted]-ray properties for the pulsar wind nebula G75.2+0.1

Abstract

Ultra-high-energy (UHE, E>0.1PeV) γ-ray sources emitting detected γ-rays with energies above 100 TeV in the Galaxy are potential candidates for the origin of the cosmic rays with energies up to 1 PeV. However, it is usually in debate whether the γ-rays are produced by protons/nuclei or electrons/positrons. Recently, photons with energies up to ∼0.27PeV from LHAASO J2018＋3651 have been detected with the Large High Altitude Air Shower Observatory (LHAASO). We investigate the origin of the γ-rays associated with the UHE source, and the detected fluxes can be reproduced via inverse Compton scattering of the electrons/positrons in the pulsar wind nebula (PWN) G75.2＋0.1. The electrons/positrons which have a spectrum of a power-law with cut-off energy powered due to spin-down of the pulsar are continuously injected into the nebula. Our results support that the UHE source originates from the PWN, and a detailed γ-ray spectrum in the range 10 TeV–1 PeV from future observations can give more insight concerning the cutoff pattern in the energy distribution of the particles injected into the nebula.