Histograms of the peak asymmetry (r_PA) of the Lyα–Lyδ and Mg II k and h lines. Individual histograms are constructed for profiles with dominating red peak (denoted with label r_B − R) and dominating blue peak (r_R − B). For all six lines, histograms for three cases are plotted with lines of different colors: Those constructed for profiles from the group 2p_ab with red, for profiles from the group 2p_a & mp_b with green line. For a combination of profiles from both these groups, the histograms are plotted with the blue line.