Detection of the Extended <i>γ</i>-Ray Emission around TeV Source 1LHAASO J0249+6022 with Fermi-LAT

Abstract 1LHAASO J0249+6022 is an extended very-high-energy γ -ray source discovered by the Large High-Altitude Air Shower Observatory. Based on nearly 16.1 yr of data from the Fermi Large Area Telescope, we report the probable γ -ray emission from 1LHAASO J0249+6022 in the 0.03–1 TeV energy range. The results show that its γ -ray spectrum can be well fitted by a single power law with an index of 1.54 ± 0.17, and integral photon flux is (4.28 ± 1.03) × 10 −11 photons cm −2 s −1 . We also considered theoretically whether the nonthermal emission could originate from a pulsar wind nebula (PWN) scenario. Assuming that the particles injected into the nebula have a power-law distribution, the resulting spectrum from the inverse Compton scattering is consistent with the detected GeV and TeV γ -ray fluxes. Our study shows that the PWN scenario is reasonable for 1LHAASO J0249+6022.