TY - JOUR

T1 - ALMA Observations of Molecular Complexity in the Large Magellanic Cloud

T2 - The N 105 Star-forming Region

AU - Sewilo, Marta

AU - Cordiner, Martin

AU - Charnley, Steven B.

AU - Oliveira, Joana M.

AU - Garcia-Berrios, Emmanuel

AU - Schilke, Peter

AU - Ward, Jacob L.

AU - Wiseman, Jennifer

AU - Indebetouw, Remy

AU - Tokuda, Kazuki

AU - van Loon, Jacco Th.

AU - Sanchez-Monge, Alvaro

AU - Allen, Veronica

AU - Chen, C. -H. Rosie

AU - Hamedani Golshan, Roya

AU - Karska, Agata

AU - Kristensen, Lars E.

AU - Kurtz, Stan E.

AU - Moeller, Thomas

AU - Onishi, Toshikazu

AU - Zahorecz, Sarolta

PY - 2022/6/1

Y1 - 2022/6/1

N2 - The Large Magellanic Cloud (LMC) is the nearest laboratory for detailed studies on the formation and survival of complex organic molecules (COMs), including biologically important ones, in low-metallicity environments-typical of earlier cosmological epochs. We report the results of 1.2 mm continuum and molecular line observations of three fields in the star-forming region N 105 with the Atacama Large Millimeter/submillimeter Array. N 105 lies at the western edge of the LMC bar with ongoing star formation traced by H2O, OH, and CH3OH masers, ultracompact H ii regions, and young stellar objects. Based on the spectral line modeling, we estimated rotational temperatures, column densities, and fractional molecular abundances for 12 1.2 mm continuum sources. We identified sources with a range of chemical makeups, including two bona fide hot cores and four hot core candidates. The CH3OH emission is widespread and associated with all the continuum sources. COMs CH3CN and CH3OCH3 are detected toward two hot cores in N 105 together with smaller molecules typically found in Galactic hot cores (e.g., SO2, SO, and HNCO) with the molecular abundances roughly scaling with metallicity. We report a tentative detection of the astrobiologically relevant formamide molecule (NH2CHO) toward one of the hot cores; if confirmed, this would be the first detection of NH2CHO in an extragalactic subsolar metallicity environment. We suggest that metallicity inhomogeneities resulting from the tidal interactions between the LMC and the Small Magellanic Cloud might have led to the observed large variations in COM abundances in LMC hot cores.

AB - The Large Magellanic Cloud (LMC) is the nearest laboratory for detailed studies on the formation and survival of complex organic molecules (COMs), including biologically important ones, in low-metallicity environments-typical of earlier cosmological epochs. We report the results of 1.2 mm continuum and molecular line observations of three fields in the star-forming region N 105 with the Atacama Large Millimeter/submillimeter Array. N 105 lies at the western edge of the LMC bar with ongoing star formation traced by H2O, OH, and CH3OH masers, ultracompact H ii regions, and young stellar objects. Based on the spectral line modeling, we estimated rotational temperatures, column densities, and fractional molecular abundances for 12 1.2 mm continuum sources. We identified sources with a range of chemical makeups, including two bona fide hot cores and four hot core candidates. The CH3OH emission is widespread and associated with all the continuum sources. COMs CH3CN and CH3OCH3 are detected toward two hot cores in N 105 together with smaller molecules typically found in Galactic hot cores (e.g., SO2, SO, and HNCO) with the molecular abundances roughly scaling with metallicity. We report a tentative detection of the astrobiologically relevant formamide molecule (NH2CHO) toward one of the hot cores; if confirmed, this would be the first detection of NH2CHO in an extragalactic subsolar metallicity environment. We suggest that metallicity inhomogeneities resulting from the tidal interactions between the LMC and the Small Magellanic Cloud might have led to the observed large variations in COM abundances in LMC hot cores.

KW - YOUNG STELLAR OBJECTS

KW - H-II REGIONS

KW - INTEGRAL FIELD SPECTROSCOPY

KW - SPECTRAL-LINE SURVEY

KW - GAS-PHASE FORMATION

KW - CHEMICAL-COMPOSITION

KW - ORGANIC-MOLECULES

KW - RADIO-CONTINUUM

KW - H2O MASERS

KW - COLOGNE DATABASE

U2 - 10.3847/1538-4357/ac4e8f

DO - 10.3847/1538-4357/ac4e8f

M3 - Journal article

VL - 931

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 102

ER -