Correlations of Methyl Formate (CH3OCHO), Dimethyl Ether (CH3OCH3) and Ketene (H2CCO) in High-mass Star-forming Regions

We present high-spatial resolution (0.7–1.0 arcsec) submillimeter observations of continuum and molecular lines of CH₃OCHO, CH₃OCH₃, and H₂CCO toward 11 high-mass star-forming regions using the Atacama large millimetre/submillimetre array (ALMA). A total of 19 separate cores from nine high-mass star-forming regions are found to be line-rich, including high-, intermediate-, and low-mass line-rich cores. The three molecules are detected in these line-rich cores. We map the emission of CH₃OCHO, CH₃OCH₃, and H₂CCO in nine high-mass star-forming regions. The spatial distribution of the three molecules is very similar and concentrated in the areas of intense continuum emission. We also calculate the rotation temperatures, column densities, and abundances of CH₃OCHO, CH₃OCH₃, and H₂CCO under the local thermodynamic equilibrium assumption. The abundances relative to H₂ and CH₃OH, and line widths of the three molecules are significantly correlated. The abundances relative to H₂, temperatures, and line widths of the three molecules tend to be higher in cores with higher mass and outflows detected. The possible chemical links of the three molecules are discussed.