Complex organic molecules (COMs, molecules containing more than 5 atoms including carbon) have been primarily
found in the environment of young protostars in the Milky Way and they may be a chemical link to the prebiotic
molecules that were involved in the process leading to the origin of life. COMs can be produced on the surface of
cold or warm dust grains (Charnley & Rodgers 2008, Garrod et al. 2006) or in gas-phase reactions in the hot gas
(Charnley et al. 1992) from methanol and formaldehyde. Therefore it is important to understand the formation
routes and evolution of these precursors as well.
I will present our Atacama Large Millimeter Array observations toward the N113 star-forming region in the Large
Magellanic Cloud (LMC). The LMC with its distance of 50 kpc and metallicity of ~0.3-0.5 solar metallicity gives
us an ideal target to study COMs and chemistry in low-metallicity environment. We identified the complex organic
molecules dimethyl ether and methyl formate, and their parent species methanol. This is the first detection of
dimethyl ether and methyl formate outside the Milky Way. The derived chemical and physical properties and the
association with water and hydroxil maser emission indicate that they are hot molecular cores (Sewilo et al.
2018).
Our ongoing Cycle 5 ALMA project is focusing on the understanding of the formaldehyde formation in high-mass
star-forming regions in our Galaxy. Our single dish APEX study suggests that formaldehyde and its deuterated
species form mostly on grain surfaces, although some gas-phase contribution is expected at the warm stage
(Zahorecz et al. 2017). Resolving the emitting region of a molecule is fundamental to understand its chemistry.
Only the higher angular resolution ALMA observations will allow us to accurately measure the column density and
to shed light on the physical conditions of the region traced by the selected molecule.
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