Zoom on the wavelength-calibrated rectified sky-subtracted 2D spectrum around the nebular emission line Hγ plotted between 1618 and 1625 nm. The wavelength scale grows from left to right, and the pixel scale perpendicular to the dispersion direction is equal to 0.2″/pixel. Residuals of two sky lines are observed on both sides of the Hγ emission. The lower trace corresponds to the Hγ emission from A2 and the upper trace to the Hγ emission from A3. In the lensed image A2, two emission components are clearly distinguishable in the 2D Hγ profile, separated in the spectral direction by  ~130 km s^-1 and in the spatial direction by  ~1″. In the lensed image A3, one can also perceive two emission components, separated in the spectral direction only and with the bluest one being significantly weaker.