Collective velocity profiles of the gaseous haloes around G1 (top) and G2 (bottom) from co-adding the observed effective optical depth of Mg ii versus velocity offset along different sightlines through each halo. Same as Figs 4 and 6, the zero velocity in each panel corresponds to the systemic redshift of the associated galaxy. The co-added velocity profiles from multiple sightlines are not a Gaussian function, indicating that the absorbing gas is not distributed randomly in each halo.