2026/07/18 by Xuefang Xu, Mingwei He, Qian Gou +10
#astro-ph.GA #astro-ph.SR
We present a uniform IRAM-30 m survey analysis of four oxygen-bearing complex organic molecules (COMs), methanol (CH3OH), acetaldehyde (CH3CHO), methyl formate (CH3OCHO), and dimethyl ether (CH3OCH3), 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 CH3CN used as a proxy excitation-temperature reference when needed. In CH3OH-normalized abundance-ratio space, CH3OCHO/CH3OH and CH3OCH3/CH3OH show the strongest pairwise correlation, whereas the correlations involving CH3CHO are weaker. No clear monotonic trends are found with Galactocentric distance or beam-averaged H2 column density. Comparison with previous observations places the CH3OCHO--CH3OCH3 behavior within the range of earlier abundance-ratio measurements, while CH3CHO 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.