Flux map of the three main emission lines on a logarithmic scale: the [O iii] doublet in red, Hβ in green and the [O ii] doublet in blue. The Hβ line is noisier than the two doublets. The flux maps were cleaned before display to mask regions with a too low signal-to-noise ratio using a threshold of 1.5 × 10^-18 erg s^-1 cm^-2 arcsec^-2 on the [O ii] surface brightness map smoothed using a 0.28′′ FWHM Gaussian. The physical scale at the redshift of the structure is indicated at the bottom right.