[O III] map (top-right) and integrated spectra of the candidate dual AGN system associated with GS551. The [O III] map is obtained by integrating the [O III] emission over a specific velocity range (as labelled), in order to highlight the primary (AGN-A) and secondary (AGN-B) nuclei, together with additional structures at the same redshift of the active galaxies. The remaining panels show the integrated spectra of the primary (top-right) and secondary (bottom-right) AGNs. The legend display the individual Gaussian components and best-fit curves shown in the spectra; best-fit total profiles are represented in red for AGN-A, and in blue for AGN-B. Residuals, defined as the difference between the observed data and the best-fit model, are displayed at the bottom of each panel, with grey shaded regions indicating the average ±3σ uncertainties on the data. The vertical green shaded area at ∼5007 Å marks the channels used to generate the [O III] map, while the blue shaded area marks those associated with extended emission marked with contours overlapping the map.