ALMA CO(1–0) continuum-subtracted spectra of the interacting galaxy pair IRAS 05054+1718: NED01 (left panels) and NED02 (right panels). The top and bottom panels display the same spectral data, but with different units on the x-axes. In particular, the top panels report the CO(1–0) flux density as a function of observed (sky) frequency, and were used to refine the systemic redshift estimates for the two galaxies (see Sect. 4.1). The bottom panels show the spectra corrected for redshift, where the CO(1–0) flux density is reported as a function of optical velocity along the line of sight. The CO(1–0) line spectrum of NED01 was extracted from an elliptical aperture maximising the CO(1–0) flux, with size 23″ × 14″, centred at RA = 05^h08^m19.858^s, Dec = +17°21′45.898″. The CO(1–0) spectrum of NED02 was extracted from an 10″ × 12″ elliptical aperture centred at RA = 05^h08^m21.212^s, Dec = +17°22′08.660″. The best-fit spectral parameters are listed in Table 2.