NOEMA observations of ID22914. Left: single-pixel extraction of the 1.2 mm spectrum of ID22914. The green dotted band gives the 1σ range of each channel. The vertical bars show the inferred [C II] redshift of ID22914 (blue long-dashed line) and of J1030+0524 (red short-dashed line). Middle: moment zero map of the [C II] line in ID22914. The field is 19″ × 19″, corresponding to the size of the primary beam. The position of the optical counterpart, located at the pointing center, is indicated by a red cross. The beam and the scale size in physical units are also reported. The contours give the ±2, 3, 4, 5σ levels, with σ = 87 mJy km s⁻¹ beam⁻¹. Positive and negative contours are shown in solid white and dotted cyan lines, respectively. ID22914 is detected at ∼3.5σ level. Right: continuum map of ID22914. The symbols are the same as in the central map, with positive and negative contours indicating the ±2, 3, 4, 5σ levels and σ = 62.3 μJy beam⁻¹. No source is detected.