In the GAS DR1, a single Gaussian velocity profile is fitted based on observations of NH3 (1, 1) and (2, 2) hyperfine line emission (see §3.1 in \citealp{Friesen2017}).  The fitting is carried out using the forward-modeling approach in the PySpecKit package \citep{Ginsburg_2011}, which was built upon the results from \citet{2008ApJS..175..509R} and \citet{2009ApJ...697.1457F} in the theoretical framework laid out by \citet{2015PASP..127..266M}.  No fitting of multiple velocity components or non-Gaussian profiles was attempted in the GAS DR1, but the single-component fitting produced good quality results in ≫95% of detections in all regions included in the GAS DR1.  Parameters derived from the fitting for the NH3 hyperfine line profiles are shown in Fig. \ref{628045}.