Effect of the source-size variation on SED fitting. Left: Effect of source size variation on the SED of a galaxy. Orange indicates the variation when the size R < 1 kpc, and a gradient of blues indicates the variation when R > 1 kpc. On the right side, we plot λ_thick (wavelength at which optical depth is unity) versus source size (R), color coded according to dust mass. These two figures show that for source sizes R < 1 kpc, there is a large effect on the peak of the SED, where the medium is optically thick, reaching higher values of λ_thick.