Turbulence and L∕M ratios of HMSCs in 2 kpc to 4 kpc. Typical errors of L∕M and Mach number are about 40% of L∕M and 1–2, respectively. The uncertainties of T_dust and line width are propagated to the calculations of Mach number. The triangles with different colors are similarto Fig. 20. The blue, orange, and red dashed lines indicate the intervals of (1) O-type AS and NA, (2) S-type AS and NA, and (3) S-type AS and O-type AS. The cyan, yellow, and pink regions show the uncertainties of the boundaries. The red and blue lines roughly outline three regions: (i) low L∕M and Mach number, (ii) intermediate L∕M and Mach number, and (iii) high L∕M and Mach number.