Molecule-dependent Abundance Behavior of Oxygen-bearing Complex Organics in High-Mass Star-Forming Regions: A Uniform 50-source Survey

We present a uniform IRAM-30,m survey analysis of four oxygen-bearing complex organic molecules (COMs), methanol (CH 3 OH), acetaldehyde (CH 3 CHO), methyl formate (CH 3 OCHO), and dimethyl ether (CH 3 OCH 3), toward 50 high-mass star-forming regions (HMSFRs) associated with 6.7,GHz methanol masers. Column densities were derived through a homogeneous rotation-diagram approach, with CH 3 CN used as a proxy excitation-temperature reference when needed. In CH 3 OH-normalized abundance-ratio space, CH 3 OCHO/CH 3 OH and CH 3 OCH 3 /CH 3 OH show the strongest pairwise correlation, whereas the correlations involving CH 3 CHO are weaker. No clear monotonic trends are found with Galactocentric distance or beam-averaged H 2 column density. Comparison with previous observations places the CH 3 OCHO--CH 3 OCH 3 behavior within the range of earlier abundance-ratio measurements, while CH 3 CHO shows larger inter-study variation. A representative warm-up chemical model is used only for qualitative comparison with the observed abundance ranges, which are most closely matched during the decline from the post-desorption abundance peaks in the model. These results provide homogeneous beam-averaged abundance-ratio constraints for common O-bearing COMs in high-mass star-forming regions and show that their source-to-source behavior is molecule-dependent rather than fully described by a single common abundance pattern.