Surface density as a function of core mass. The IR dark cores (no WISE counterpart) are shown by blue data points, while the red data points show the IR bright cores (cores with a WISE counterpart). The H II region IRAS 13037-6112a is indicated by a green data point. The two horizontal dashed lines show the threshold surface densities for high-mass star formation proposed by López-Sepulcre et al. (2010; black) and Urquhart et al. (2014; magenta) when scaled to the present assumptions about the dust properties (see Sect. 4.2).