TY - JOUR

T1 - The Detection of Deuterated Water in the Large Magellanic Cloud with ALMA

AU - Sewilo, Marta

AU - Karska, Agata

AU - Kristensen, Lars E.

AU - Charnley, Steven B.

AU - Chen, C-H Rosie

AU - Oliveira, Joana M.

AU - Cordiner, Martin

AU - Wiseman, Jennifer

AU - Sanchez-Monge, Alvaro

AU - van Loon, Jacco Th

AU - Indebetouw, Remy

AU - Schilke, Peter

AU - Garcia-Berrios, Emmanuel

PY - 2022/7/5

Y1 - 2022/7/5

N2 - We report the first detection of deuterated water (HDO) toward an extragalactic hot core. The HDO 2(11)-2(12) 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 (L (HDO)) measured toward the LMC hot cores to those observed toward a sample of 17 Galactic hot cores covering three orders of magnitude in L (HDO), four orders of magnitude in bolometric luminosity (L (bol)), and a wide range of Galactocentric distances (thus metallicities). The observed values of L (HDO) for the LMC hot cores fit very well into the L (HDO) trends with L (bol) and metallicity observed toward the Galactic hot cores. We have found that L (HDO) 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.

AB - We report the first detection of deuterated water (HDO) toward an extragalactic hot core. The HDO 2(11)-2(12) 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 (L (HDO)) measured toward the LMC hot cores to those observed toward a sample of 17 Galactic hot cores covering three orders of magnitude in L (HDO), four orders of magnitude in bolometric luminosity (L (bol)), and a wide range of Galactocentric distances (thus metallicities). The observed values of L (HDO) for the LMC hot cores fit very well into the L (HDO) trends with L (bol) and metallicity observed toward the Galactic hot cores. We have found that L (HDO) 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.

KW - YOUNG STELLAR OBJECTS

KW - H-II-REGIONS

KW - COMPLEX ORGANIC-MOLECULES

KW - INFRARED SPECTRAL ATLAS

KW - STAR-FORMING REGIONS

KW - HIGH-MASS PROTOSTAR

KW - CHEMICAL-COMPOSITION

KW - ABUNDANCE GRADIENTS

KW - PHYSICAL CONDITIONS

KW - ROTATING TOROIDS

U2 - 10.3847/1538-4357/ac6de1

DO - 10.3847/1538-4357/ac6de1

M3 - Journal article

VL - 933

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 64

ER -