Abstract

Hot cores, as a stage of massive star formation, exhibit abundant line emissions of complex organic molecules (COMs). We present a deep line survey of two isomers of C2H6O: ethanol (C2H5OH; EA), and dimethyl ether (CH3OCH3; DE) as well as their possible precursor CH3OH towards 60 hot cores by using the Atacama Large Millimeter/submillimeter Array (ALMA) 3 mm line observations. EA is detected in 40 hot cores and DE is detected in 59 hot cores. Of these, EA and DE are simultaneously detected in 39 hot cores. We calculate rotation temperatures and column densities of EA and DE by using the eXtended CASA Line Analysis Software Suite (XCLASS) software. The average rotation temperature of EA is higher than that of DE, whereas the average column density of EA is lower than that of DE. Combined with previous studies of hot cores and hot corinos, we find strong column density correlations among EA and DE (? = 0.92), EA and CH3OH (? = 0.82), as well as DE and CH3OH (? = 0.80). The column density ratios of EA/DE versus the column densities of CH3OH remain nearly constant with values within ?1 order of magnitude. These strong correlations and the stable ratios, suggest that EA, DE, and CH3OH could be chemically linked, with CH3OH potentially serving as a precursor for EA and DE. Compared with chemical models, the three different warm-up time-scale models result in the systematic overproduction of EA and the systematic underproduction of DE. Therefore, our large sample observations can provide crucial constraints on chemical models. © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.