Magellanic Outflow and Chemistry Survey (MAGOS): Hot Cores in the LMC

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Abstract The Large Magellanic Cloud (LMC) provides a key laboratory for exploring the diversity of star formation and interstellar chemistry under subsolar metallicity conditions. We present the results of a hot core survey toward 30 massive protostellar objects in the LMC using the Atacama Large Millimeter/submillimeter Array at 350 GHz. Continuum imaging reveals 36 compact sources in total, among which line analyses identify nine hot cores and one hot-core candidate, including two newly identified sources. We detect CO, HCO+, H 13 CO + , HC 15 N, HC 3 N, SiO, SO, SO + , NS, SO 2 , 34 SO 2 , 33 SO 2 , CH 3 OH, 13 CH 3 OH, HCOOH, HCOOCH 3 , CH 3 OCH 3 , C 2 H 5 OH, H 2 CCO (tentative), and hydrogen recombination lines from hot cores. CH 3 OCH 3 , a complex organic molecule (COM) larger than CH 3 OH, is detected for the first time in a hot core outside the LMC bar region. All hot cores show stronger emission in the high-excitation SO line compared to non-hot-core sources, suggesting that its strong detection will be useful for identifying hot-core candidates in the LMC. Chemical analysis reveals a spread of more than 2 orders of magnitude in CH 3 OH abundances, with some sources deficient in COMs. In contrast, SO 2 is detected in all hot cores, and its abundance shows a good correlation with rotational temperature. The hot cores without CH 3 OH detections are all located outside the LMC bar region and are characterized by either high luminosity or active star formation in their surroundings. A combination of locally low metallicity, active star formation in the vicinity, and high protostellar luminosity may jointly trigger the COM-poor hot-core chemistry observed in the LMC.

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