Radial profiles of the Fourier amplitudes of density: (a) shows a simple bar, whereas (b) shows a two-component bar: both lower and higher Fourier modes are significant in these two components. The thin lines show the Fourier’s amplitudes, normalized to . The thick grey line shows the force ratio ( indicates the maximum of ), and the vertical line indicates the length of the bar. The crosses show individual Gaussian fits to the Fourier’s amplitude profile. The single-peaked bar represents a thin classical bar. The double-peaked amplitude profile is associated to a bar having a shorter and vertically thicker inner part and a longer and vertically thinner outer part. This figure is a modified version of Figure 8 in Laurikainen et al. [34].
