Voigt profile fitting of four multiplets of C I. The spectrum is shown as the black line with the best-fitting model overlaid as the solid red curve. Each of the blue tick marks indicates the position of a velocity component of either the ground level (J = 0) or the two excited fine-structure levels (J = 1 and J = 2). The small panel on top of each sub-figure shows the residuals of the fit in the given region.