Mid-IR to millimeter SED of GN20 in observed wavelength. Left: complement our new continuum measurements at 1.86 and 3.05 mm (red points) with existing photometry observations at observed and λ > 160 μm and λ ≤ 160 μm (black and grey points, respectively), where the latter is omitted from the MBB modeling. Blue and red lines show the best-fit single-temperature MBB prescription assuming an optically thick (λ₀ = 170 ± 23 μm) and thin dust emission, respectively. We also present the best-fit MBB model when accounting for the effect of the CMB (grey curve). The solid pink line shows the best-fit using the DL07 dust models, containing a diffuse ISM component and dust in PDR regions. The best-fit MBB parameters are listed in Table 1. Right: zoom-in of the rest-frame FIR part of the SED of GN20 when including the optically thick and thin MBB prescriptions. We note that the optically thick MBB model is a better macth to the photometry observations at λ ≤ 160 μm.