Spatially integrated Balmer line emission for Case A (thick line) and Case B (thin line). The dashed lines show the best fit obtained using a two-Gaussian fit. In the bottom panel the Balmer emission is convolved with an instrumental resolution of 125     km   s^-1, which corresponds to a FWHM of 350     km   s^-1. In this case the wings disappear and the emission can be fitted well with two-Gaussian curves (dashed lines).