CO, HCO⁺, SiO, and H¹³CO⁺ average spectra over the angular size of M − 3.8+0.9 cloud (from l =  − 40 to  − 3625, and from b = 05625 to 11875). The angular size considered for each region is listed in Table 2. The red lines indicate the Gaussian fit for the complete region and blue dashed lines show the Gaussian fits of each velocity components.