300 GeV) into six bins and impose a TS threshold of 1 per energy bin for the flux calculation; otherwise an upper limit is calculated. In each bin, the photon indexes of the sources of interest are fixed to 2 to avoid any dependence on the spectral models. The fluxes of the PWN and the SNR components are let free during the fit as well as those of the Galactic and isotropic diffuse emissions. All other sources are fixed to their best global model.

Figure \[fig:SEDs\] shows the SED of the uniform disk (left) and the SED of the best-fit two-component model (right) using the radio PWN and the SNR mask. The colored error bars represent the statistical errors while the quadratic sums of the statistical and systematic errors [calculated using eight alternative Galactic diffuse emission models as explained in the first $\textit{Fermi}$-LAT supernova remnant catalog, @First_SNRcat:2016] are represented with black horizontal bars. The systematic errors are never dominant and are comparable to the statistical ones only in the first band. Note that the effective area uncertainty also induces systematic errors (10% between 100 MeV and 100 GeV). These SEDs clearly emphasize that two distinct morphologies give rise to two 