Narrow Hα emission from the residual K-band fitting, extracted from a ring-shaped region (0.5′′<r< 0.8′′) of LBQS0109 (top) and HB8903 (bottom). The red arrows indicate the expected position at the redshift of the [Oiii]_nar component. The dashed red line indicates the expected positions for doublet [Nii]: the lines are not detected, confirming that star formation is the excitation mechanism for the narrow Hα line (see text).