Radial profiles of various properties during the collapse of a 1  M_⊙ dense clump at a core central density ρ_c = 10^-8  g   cm^-3 for the grey (grey thick solid line) and multigroup (colours) models. For the multigroup run, the gas and total radiative (summed over all groups) quantities are plotted in red, while the other colours represent the individual groups; see legend in e). From top left to bottom right: a) density; b) gas (solid) and radiation (dashed) temperature; c) velocity; d) entropy; e) optical depth; f) luminosity; g) Planck average opacity; and h) reduced radiative flux.