Pure-line visibility fits for August 19^th (left column) and 20^th (right column). Each row consists of two subplots : The top one includes the pure-line visibilities squared and their 1σ uncertainty observed at a given velocity (mentioned in the panel) superimposed with the corresponding model including a Gaussian disk and a halo. The bottom one illustrates the residuals of the model in units of σ. Three shades of gray mark the 1-,3-, and 5σ levels. The color of the data points corresponds to the baseline.