= 0.5$$ where $R_{12.5}$ = $R$/(12.5 pc) and $t_{4}$ = $t$/(10,000 yrs) taking $R$ = 21 pc, $t$ = 16,500 yrs and $n_{0}$ = 0.1 cm$^{-3}$ for a distance of 4.1 kpc. We take the inputs from [@Temim:2013] but do not derive the same explosion energy. Here we use the common values of $\xi$ = 2.026 (for $\gamma$ = 5/3) and $\rho_{0}$ = 1.4$m_{\rm{H}}n_{0}$ in the usual Sedov equation: $R^{5}$ = $\xi$ ($E_{\rm{SN}}$/$\rho_{0}$) $t^{2}$.

The explosion energy and age depend on the distance, which is still uncertain. In addition, the density and temperature (the latter provides the shock speed estimate) were derived from a small region in the south of the SNR and it is not yet clear whether this region is representative of the rest of the SNR. (A Large Program with *XMM-Newton* on G326.3$-$1.8 is currently ongoing and will provide more constraints on the thermal emission across the SNR.) In this regard, the multi-wavelength modeling presented in this section is not to be viewed as a precise measurement of the properties of the accelerated particles but rather as showing that a simple self-consistent model can reproduce the observations.

We describe the electron population as a broken power law 