Spectral energy distribution (SED) from the sub-millimeter to centimeter wavelengths. Top: SED of the whole dist. The thick red line depicts a fit to centimeter data, while the blue one shows a fit to sub-millimeter and millimeter data. The thick black curve shows the combined fit. Blue dots are observations from this paper (millimeter data) and the literature (sub-millimeter and centimeter). Black triangles are fluxes from the central source alone. Bottom: SED of the compact source towards the center after subtracting the free-free contribution.