Position-velocity diagram of a slice running at a position angle of 128° and with a width of 125 covering the central part of the outflow centred on source A1. The velocity has been shifted so the source velocity is at 0 km s^-1 (black line). Signal below the 3σ level is ignored as are the central  ± 3 km s^-1. The position of source A1 is marked with a dotted line. Negative offsets are towards the SE, positive towards NW.