Excitation temperature as a function of central velocity for the six O-bearing COMs. The top panel shows the results from sin- gle component fitting, and the bottom panel shows the results from the multicomponent fit. The size of the circle represents the source size; the CH₂(OH)CHO circle has a dashed outline since the source size of CH₂(OH)CHO can be degenerate with column density due to a lack of optically thick transition. The dashed circle at the bottom-right corner indicates a size of 0.3 arcsec.