Lower panel: number of Ca ii, Na i and H i detections versus Doppler-parameter (b-value). Median values for the Doppler parameter are b = 3.3 km ^-1 for Ca ii and b = 2.1 km ^-1 for Na i. For neutral atomic hydrogen the b-values have an enormous spread, which can most likely be explained with substructure since the spatial resolution of the 21-cm data is very coarse. For convenience we show in the upper panel the equivalent maximal (kinetic) temperatures associated with the b-values.