Probability distribution functions P(η) of the velocity components probed with c-C₃H₂. The velocity of the component is indicated at the bottom of each panel in km s⁻¹. The right y-axis indicates thenumber of pixels counted in each bin. The mean opacity is given in the upper right corner and the parameters of the fitted Gaussian(s) in the upper left corner: dispersion σ, integral A, and centre μ.