The Detection of Hot Cores and Complex Organic Molecules in the Large Magellanic Cloud

Abstract

We report the first extragalactic detection of the complex organic molecules (COMs) dimethyl ether (CH${}_3$OCH${}_3$) and methyl formate (CH${}_3$OCHO) with the Atacama Large Millimeter/submillimeter Array (ALMA). These COMs together with their parent species methanol (CH${}_3$OH), were detected toward two 1.3 mm continuum sources in the N 113 star-forming region in the low-metallicity Large Magellanic Cloud (LMC). Rotational temperatures ($T_{\mathrm{rot}}\sim 130$ K) and total column densities ($N_{\mathrm{rot}}\sim 10^{16}$ cm${}^{-2}$) have been calculated for each source based on multiple transitions of CH${}_3$OH. We present the ALMA molecular emission maps for COMs and measured abundances for all detected species. The physical and chemical properties of two sources with COMs detection, and the association with H${}_2$O and OH maser emission indicate that they are hot cores. The fractional abundances of COMs scaled by a factor of 2.5 to account for the lower metallicity in the LMC are comparable to those found at the lower end of the range in Galactic hot cores. Our results have important implications for studies of organic chemistry at higher redshift.

10 pages, 4 figures

References in corpus (6)

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• The Detection of Hot Molecular Cores in the Small Magellanic Cloud
• CHEMOUT: CHEMical complexity in star-forming regions of the OUTer Galaxy. I. Organic molecules and tracers of star-formation activity
• Herschel spectroscopy of Massive Young Stellar Objects in the Magellanic Clouds
• An ALMA Glimpse of Dense Molecular Filaments Associated with High-mass Protostellar Systems in the Large Magellanic Cloud
• Testing the weak equivalence principle by differential measurements of fundamental constants in the Magellanic Clouds
• Glycolaldehyde formation mediated by interstellar amorphous ice: a computational study
• Infrared action spectroscopy as tool for probing gas-phase dynamics: Protonated Dimethyl Ether, (CH${}_3$)${}_2$OH${}^{+}$, formed by the reaction of CH${}_3$OH${}_2^{+}$ with CH${}_3$OH
• Interrelations between Astrochemistry and Galactic Dynamics
• Molecular Formation in Low-Metallicity Hot Cores