6″ × 6″ cutouts of L_UV binned stacks of ALMA continuum images used to derive the stacked dust masses. The upper and lower panels show stacks of galaxies at z ∼ 4.5 and z ∼ 5.5, respectively. The black solid contours show 2, 3, 4, 5σ. In the z ∼ 4.5 bins all stacks have a clear detection at > 4σ, but in the z ∼ 5.5 bins the stacks have a clear detection only at the highest L_UV bin. In Table 1 the results of the stacking analysis are summarised, including the number of sources stacked in each bin of L_UV.