L1527 ALMA 88 GHz (purple), 100 GHz (orange), 141 GHz (green), 249 GHz (blue), 348 GHz (red) visibility amplitudes up to 1000 kλ. We also compare the 94 and 231 GHz observations (white points) performed with the Plateau de Bure Interferometer (PdBI) and anlayzed in Galametz et al. (2019). The slope of our observed Spectral Energy Distribution (black line) has been obtained by fitting a line to the fluxes at all wavelengths in each uv-distance bin. While 1.5 < α_fit < 2.5, most of the contribution to the flux – and to α – at any uv-distance is due to the disk (see Sect. 4).