Example of the method implemented in this work to evaluate the smoothness of the NIR-MIR transition of the SED constructed for every UKIDSS source and the corresponding R08 object. For each one of the three UKIDSS sources detected for the R08 object SSTGLMC G048.9610−00.3963 (the same shown in Fig. 4), we plot the combined NIR-MIR SED overlaid with its cubic spline representation (yellow line) and the quadratic function fitted over the 4 middle points (H, K, 3.6 μm, and 4.5 μm filters; gray line). The value for the mean ratio of both curves as defined in Eq. (1) is indicated at the lower left corner of each panel. Colors for the SED points are as in the right panel of Fig. 4. In this particular example, the J upper limits have been simply ignored by the method (see the text for details on how different cases like this are treated).