ALMA Observations of Molecular Complexity in the Large Magellanic Cloud: The N105 Star-Forming Region

Abstract

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 for earlier cosmological epochs. We report the results of 1.2 mm continuum and molecular line observations of three fields in the star-forming region N105 with the Atacama Large Millimeter/submillimeter Array (ALMA). N105 lies at the western edge of the LMC bar with on-going star formation traced by H${}_2$O, OH, and CH${}_3$OH 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 twelve 1.2 mm continuum sources. We identified sources with a range of chemical make-ups, including two bona fide hot cores and four hot core candidates. The CH${}_3$OH emission is widespread and associated with all the continuum sources. COMs CH${}_3$CN and CH${}_3$OCH${}_3$ are detected toward two hot cores in N105 together with smaller molecules typically found in Galactic hot cores (e.g., SO${}_2$, SO, and HNCO) with the molecular abundances roughly scaling with metallicity. We report a tentative detection of the astrobiologically relevant formamide molecule (NH${}_2$CHO) toward one of the hot cores; if confirmed, this would be the first detection of NH${}_2$CHO in an extragalactic sub-solar metallicity environment. We suggest that metallicity inhomogeneities resulting from the tidal interactions between the LMC and the Small Magellanic Cloud (SMC) might have led to the observed large variations in COM abundances in LMC hot cores.

75 pages, 48 figures, 7 tables (including appendices); Accepted for publication in the Astrophysical Journal

References in corpus (41)

• Cosmic Star Formation History
• Physical Properties of Wolf-Rayet Stars
• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Photochemistry and astrochemistry: photochemical pathways to interstellar complex organic molecules
• Testing grain-surface chemistry in massive hot-core regions
• The origin of complex organic molecules in prestellar cores
• SiO line emission from C-type shock waves : interstellar jets and outflows
• A 2 mm spectral line survey of the starburst galaxy NGC 253
• The VISTA Science Archive
• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
• Shedding light on the formation of the pre-biotic molecule formamide with ASAI
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the Magellanic Clouds
• Seeds of Life in Space (SOLIS) III. Formamide in protostellar shocks: evidence for gas-phase formation
• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. II. Gas-to-Dust Ratio Variations across ISM Phases
• Sensitivity analysis of grain surface chemistry to binding energies of ice species
• Molecules with a peptide link in protostellar shocks: a comprehensive study of L1157
• Chemical modelling of complex organic molecules with peptide-like bonds in star-forming regions
• Interstellar formamide (NH${}_2$CHO), a key prebiotic precursor
• Abundances and Isotope Ratios in the Magellanic Clouds: The Star Forming Environment of N113
• The Evolution of Massive YSOs in the LMC: Part I. Identification and Spectral Classification
• Efficiency of non-thermal desorptions in cold-core conditions. Testing the sputtering of grain mantles induced by cosmic rays
• Hydrogenation at low temperatures does not always lead to saturation: the case of HNCO
• The Detection of Hot Cores and Complex Organic Molecules in the Large Magellanic Cloud
• Dynamical Influences of the Last Magellanic Interaction On the Magellanic Clouds
• Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud
• Chemical distribution of HII regions towards the Galactic anticentre
• The Magellanic Squall: Gas Replenishment from the Small to Large Magellanic Cloud
• AKARI Near Infrared Spectroscopy: Detection of H2O and CO2 Ices toward Young Stellar Objects in the Large Magellanic Cloud
• Massive Young Stellar Objects in the Large Magellanic Cloud: water masers and ESO-VLT 3-4 micron spectroscopy
• Chemical Segregation in Hot Cores With Disk Candidates: An investigation with ALMA
• Deep K-band observations of TMC-1 with the Green Bank Telescope: Detection of HC7O, non-detection of HC11N, and a search for new organic molecules
• A population of hypercompact HII regions identified from young HII regions
• $K$-band integral field spectroscopy and optical spectroscopy of massive young stellar objects in the Small Magellanic Cloud
• Evolution of dust and molecular hydrogen in the Magellanic System
• Evaporation of grain-surface species by shock waves in proto-planetary disk
• The ASKAP-EMU Early Science Project: 888 MHz Radio Continuum Survey of the Large Magellanic Cloud
• Herschel spectroscopy of Massive Young Stellar Objects in the Magellanic Clouds
• Cold Water Vapor in the Barnard 5 Molecular Cloud
• The TOPGöt high-mass star-forming sample. I. Methyl cyanide emission as tracer of early phases of star formation

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• The Detection of Hot Molecular Cores in the Small Magellanic Cloud
• An ALMA Glimpse of Dense Molecular Filaments Associated with High-mass Protostellar Systems in the Large Magellanic Cloud
• CHEMOUT: CHEMical complexity in star-forming regions of the OUTer Galaxy. II. Methanol formation at low metallicity
• Near-infrared spectroscopy of embedded protostars in the massive metal-poor star-forming region NGC 346
• The Detection of Deuterated Water in the Large Magellanic Cloud with ALMA
• An ALCHEMI inspection of sulphur-bearing species towards the central molecular zone of NGC 253
• Protostars at Subsolar Metallicity: First Detection of Large Solid-state Complex Organic Molecules in the Large Magellanic Cloud
• CHEMOUT: CHEMical complexity in star-forming regions of the OUTer Galaxy. V. Chemical composition gradients as a function of the galactocentric radius
• MAGellanic Outflow and chemistry Survey (MAGOS): Hot cores in the LMC
• First detection of CF${}^{+}$ in the Large Magellanic Cloud
• Chemistry of Dark Molecular Clouds
• Molecular Formation in Low-Metallicity Hot Cores