Comparison of the Hα lines of the three components of J1608+2716. Left panels, from top to bottom: A, B, and C components, color-coded as in Fig. 1. Each panel shows the observed emission line scaled to the same flux of component A, and fit with a Gaussian profile plus a constant (shown as a thick solid line with the same color as the corresponding component). The center of the best-fitting Gaussian is reported as a vertical dashed line. For an easy comparison, the fit to component A (the brightest component) is also shown on top of components B and C. Right panels: distributions of the values of centroids and FWHM for the Gaussian fit on 4000 stochastic realizations of the observed spectra, each obtained by injecting noise into the data.