Gemini-N/GMOS spectra of HULQ J0002+0239. Top panel: 2D spectra of the central QSO and the two objects. Center panel: spectra of the two objects, A and C. The spectra of objects A and C are shown in blue and orange, respectively. The spectra are offset by 0.5 × 10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹ for clarity, and the horizontal black dashed lines represent zero flux for each spectrum. The HSC i-band magnitude of object A is shown with a red square, with the horizontal error bars indicating the bandwidth. For object A, wavelengths of emission lines from an object at z = 0.293 are indicated with vertical purple dotted lines. For object C, wavelengths of emission lines from objects at z = 0.197, 0.616, and 1.108 are shown with vertical red, blue, and green dotted lines, respectively. These redshifts correspond to the redshifts of the source when the single strong emission line at ∼7860 Å corresponds to Hα, Hβ, and [O II], respectively. Vertical gray regions indicate the positions of the CCD gaps. Bottom panel: sky emission in arbitrary units.