Spectral energy distribution of RCW 86 with the best-fit leptonic (top) and hadronic (bottom) models. The radio data points are from Molonglo at 408 MHz and Parkes at 5 GHz (Caswell et al. 1975; Green 2011, priv. comm.), and lower limits from MOST at 843 MHz and ATCA at 1.43 GHz (Whiteoak & Green 1996; Dickel et al. 2001). X-ray spectra from ASCA and RXTE were obtained as described in Sect. 3. The Fermi-LAT upper limits (99.9% C.L.) derived in Sect. 2.2 and the H.E.S.S. data points in the VHE domain (Aharonian et al. 2009) are also shown. For each plot, the blue (respectively red) lines denote the total broadband emission from the one-zone (respectively two-zone) modeling discussed in Sect. 4, with SC, IC (with CMB only) and π⁰ spectra shown as solid, dashed, and dash-dotted lines, respectively. The associated best-fit parameters are provided in Table 2. Note that in the bottom panel, π⁰ emission is similar for the two models, and equals the total gamma-ray emission in the one-zone model (solid blue line). In addition, the dotted black line shows the (excluded) case of π⁰ emission from a E^-2 hadron spectrum with / and E_max,p = 100 TeV.