Mean local density versus redshift for the CDFS (upper panel) and for the UDS (lower panel) shown as dashed solid curves. The mean corresponds to the average of the local density values in each bins of Δz = 0.02, after the application of sigma clipping, as explained in the text. Vertical solid lines represent the redshifts of the detected overdensities. In the lower panel, vertical dashed lines correspond to two slightly lower-threshold overdensities at z ∼ 2.8 (THRESHOLD = 4 instead of 6).