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The Detection of Deuterated Water in the Large Magellanic Cloud with ALMA

Sewiło, Marta; Karska, Agata; Kristensen, Lars E.; Charnley, Steven B.; Rosie Chen, C.-H.; Oliveira, Joana M.; Cordiner, Martin; Wiseman, Jennifer; Sánchez-Monge, Álvaro; Van Loon, Jacco Th.; Indebetouw, Remy; Schilke, Peter; Garcia-Berrios, Emmanuel

The Detection of Deuterated Water in the Large Magellanic Cloud with ALMA Thumbnail


Authors

Marta Sewiło

Agata Karska

Lars E. Kristensen

Steven B. Charnley

C.-H. Rosie Chen

Martin Cordiner

Jennifer Wiseman

Álvaro Sánchez-Monge

Remy Indebetouw

Peter Schilke

Emmanuel Garcia-Berrios



Abstract

We report the first detection of deuterated water (HDO) toward an extragalactic hot core. The HDO 211–212 line has been detected toward hot cores N 105–2 A and 2 B in the N 105 star-forming region in the low-metallicity Large Magellanic Cloud (LMC) dwarf galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA). We have compared the HDO line luminosity (LHDO) measured toward the LMC hot cores to those observed toward a sample of 17 Galactic hot cores covering three orders of magnitude in LHDO, four orders of magnitude in bolometric luminosity (Lbol), and a wide range of Galactocentric distances (thus metallicities). The observed values of LHDO for the LMC hot cores fit very well into the LHDO trends with Lbol and metallicity observed toward the Galactic hot cores. We have found that LHDO seems to be largely dependent on the source luminosity, but metallicity also plays a role. We provide a rough estimate of the H2O column density and abundance ranges toward the LMC hot cores by assuming that HDO/H2O toward the LMC hot cores is the same as that observed in the Milky Way; the estimated ranges are systematically lower than Galactic values. The spatial distribution and velocity structure of the HDO emission in N 105–2 A is consistent with HDO being the product of the low-temperature dust grain chemistry. Our results are in agreement with the astrochemical model predictions that HDO is abundant regardless of the extragalactic environment and should be detectable with ALMA in external galaxies.

Acceptance Date May 6, 2022
Publication Date Jul 5, 2022
Publicly Available Date Mar 29, 2024
Journal The Astrophysical Journal: an international review of astronomy and astronomical physics
Print ISSN 0004-637X
Publisher American Astronomical Society
DOI https://doi.org/10.3847/1538-4357/ac6de1
Keywords Star formation; Astrochemistry; Magellanic Clouds; Chemical abundances; Star forming regions; Protostars
Publisher URL https://iopscience.iop.org/article/10.3847/1538-4357/ac6de1

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