Emission line maps and spectra of TN J0121+1320 showing the [O III] companion search. (a, b): [O III]5007 channel maps. Each map is integrated over three consecutive wavelength channels (i.e., ∼150 km s⁻¹). The central velocity is marked at the top right corner. We mark the position of the radio AGN with a magenta star. The position of [O III] companion and the [C II] companions are marked by a blue triangle and red square, respectively. The position of the foreground galaxy is marked with a blue dot. The ALMA 400 GHz continuum is shown as white contours (levels of [0.35, 0.63, 1.1, 2.0, 3.0] mJy beam⁻¹). The 8 GHz radio emission is shown as green contours. We illustrate the sizes of the NIRSpec IFU PSF (gray) and the synthesized beam of ALMA 400 GHz (θ_400 GHz white) at the bottom left of each panel. (c): [O III]4959, 5007 spectra at the positions of the radio AGN (upper) and J0121-[O III] (lower). These continuum-subtracted spectra were extracted using r = 0.1″ apertures. The best fits from q3dfit are in dark magenta. Different Gaussian components are shown in shaded colors. The fitted Gaussian component of J0121-[O III] is highlighted in dark red. The vertical shaded regions mark the velocity ranges where the channel maps in panels (a, b) are integrated. The projected distance between the [O III] companion and radio core is marked at the top right corner of the lower panel. (d): Velocity map of J0121-[O III] constructed from the q3dfit fitting. The markers and contours are the same as in panels (a, b). (e): Example [O III]4959, 5007 spectra from two spaxels showcasing the different kinematics across J0121-[O III]. The Gaussian components are highlighted in blue and red for bluer and redder Δv, respectively.