Radial profiles of the stacked [C II] line and FIR continuum emission. (Left) Normalized radial surface density profile of the uv-stacked image in [C II] line (R_e, [CII] = 1.97 ± 0.17 kpc) and FIR continuum (R_e, FIR = 1.53 ± 0.22 kpc) emission. The dotted lines show average surface density derived by setting random apertures on blank regions, which are also shown in color-shaded regions as uncertainties. The dashed black curve represents the clean PSF. The top axis is converted to a physical scale assuming an average redshift of z = 5.22 among the stacked sample. (Right) Absolute radial surface density profiles of the [C II] line and FIR continuum emission, in which the unit is converted to L_⊙/kpc². The solid black line shows the ratio between the [C II] line and IR emission (axis shown on the right hand side). As we do not see a strong radial variation in the [C II]-to-IR luminosity ratio, we suggest that the [C II] deficit is not responsible for the extended [C II] line emission.