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A second extragalactic pulsar wind nebula (PWN) is discovered in the MeV-GeV band using the Fermi-LAT. Faint, point-like -ray emission is detected at the location of the composite supernova remnant (SNR) B0453-685 from energies 300 MeV - 2 TeV. The Fermi-LAT data analysis of the new -ray source is presented together with a detailed multi-wavelength investigation to understand the nature of the observed emission. The observational evidence and physical implications from broadband modeling do not support an SNR -ray origin. Semi-analytic radiative evolutionary models are explored to understand the potential for any pulsar or PWN component responsible for the observed -ray emission. The modeling results favor an evolved PWN (14, 000 years) that has been impacted by the return of the SNR reverse shock with a possible substantial pulsar component below 5 GeV. The particle acceleration mechanisms and their efficiency within B0453-685 have important implications for the role PWNe play in generating Cosmic Rays (CRs), but constraints on the synchrotron cut-off are required to accurately characterize the underlying particle properties.
Eagle et al. (Wed,) studied this question.