Two example fits of the observations with the Gaussian components and with the pseudo-Voigt profile. The upper panel corresponds to the nearly ideal case for the fitting with the pseudo-Voigt profile and the lower panel represents the typical situation. Thick lines correspond to the observations and the models. Thin lines illustrate the Gaussian and the Lorentzian contributions to the final models. Crosses mark the points, which define FWHM_WMS in two different models.