The rotation diagram derived from (a) HNCO transitions and (b) SiO transitions in all selected regions. The uncertainty is propagated from the measured error from the line intensity. The color coding indicates data from each region selected as shown in the schematic in Fig. 6d. The faded (gray-ish) marks indicate data points below 3.0σ cut, to which case we will use 3.0σ as upper limit in our further analysis. The fitted rotational temperature are list in Table A.1.