Emission lines of one double-peak galaxy classified as a merger (Domínguez Sánchez et al. 2018) at z = 0.057, namely H_βλ4863, [OIII]λ5008, [OI]λ6302, [NII]λ 6550, H_αλ6565, [NII]λ 6586, [SII]λ6718 and [SII]λ 6733. Top left: SDSS snap-shot. Each displayed line is fitted with a double Gaussian function (with velocities fixed with the stacked spectra) as displayed by blue and red lines. The black dashed line indicates the position of the stellar velocity of the host galaxy, computed by Chilingarian et al. (2017). As in Maschmann et al. (in prep.), we indicate emission lines with a confirmed double-peak “with DP” (resp. “no DP”). Beside S/N constraints, the non-detection corresponds to a line weaker than a factor of three.