MCMC fit of observed, unblended, optically thin transitions of vinyl cyanide and its isotopologues (solid green lines). The blue lines represent the modeled spectra, whereas the observed spectra are shown in black. The vertical red dashed line shows the position of V_lsr = 68 km/s. The green solid lines represent the LTE spectra of some species by considering the rotational temperature and column density obtained from the rotational diagram analysis (see Fig. 1).