Channel maps from the R2700 cube targeting the [O III]λ5007 Å emission line. Black lines are the contour of the 5, 25, and 75 times the RMS level computed in the line-free regions of the cube for the emission at v = 0. The velocity marks the central velocity of the channel. The black cross shows the location of the [C II] emission peak (see Fig. 1). The white circles represent the position of the components of HZ4.