KDE distribution of the non-thermal line widths to sound speed ratios in G035.39, peaking at ℳ = 0.91. The upper axis shows equivalent velocity dispersions for T_kin = 12 K, a mean temperature in our sample. A subsample extracted from pixels within one synthesized beam of the VLA around the 70 μm Herschel sources (Nguyen Luong et al. 2011) is shown in orange,alongside the remaining data plotted in blue. Overplotted for the reference are the mean values for starless and protostellar IRDC cores found in Sánchez-Monge et al. (2013).