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dc.contributor.authorWilliams, Gwenllian M.
dc.contributor.authorCyganowski, Claudia J.
dc.contributor.authorBrogan, Crystal L.
dc.contributor.authorHunter, Todd R.
dc.contributor.authorNazari, Pooneh
dc.contributor.authorSmith, Rowan J.
dc.identifier.citationWilliams , G M , Cyganowski , C J , Brogan , C L , Hunter , T R , Nazari , P & Smith , R J 2023 , ' ALMA observations of the Extended Green Object G19.01-0.03 : II. A massive protostar with typical chemical abundances surrounded by four low-mass prestellar core candidates ' , Monthly Notices of the Royal Astronomical Society , vol. 525 , no. 4 , pp. 6146-6169 .
dc.descriptionFunding: GMW acknowledges support from the UK’s Science and Technology Facilities Council (STFC) under ST/W00125X/1. CJC acknowledges support from the UK’s STFC under ST/M001296/1. PN acknowledges support by grant 618.000.001 from the Dutch Research Council (NWO) and support by the Danish National Research Foundation through the Center of Excellence "InterCat" (Grant agreement no.: DNRF150).en
dc.description.abstractWe present a study of the physical and chemical properties of the Extended Green Object (EGO) G19.01−0.03 using sub-arcsecond angular resolution Atacama Large Millimeter/submillimeter Array (ALMA) 1.05 mm and Karl G. Jansky Very Large Array (VLA) 1.21 cm data. G19.01−0.03 MM1, the millimetre source associated with the central massive young stellar object (MYSO), appeared isolated and potentially chemically young in previous Submillimeter Array observations. In our ∼0.4″-resolution ALMA data, MM1 has four low-mass millimetre companions within 0.12 pc, all lacking maser or outflow emission, indicating they may be prestellar cores. With a rich ALMA spectrum full of complex organic molecules, MM1 does not appear chemically young, but has molecular abundances typical of high-mass hot cores in the literature. At the 1.05 mm continuum peak of MM1, N(CH3OH) = (2.22 ± 0.01) × 1018 cm−2 and Tex=162.7+0.3−0.5 K based on pixel-by-pixel Bayesian analysis of LTE synthetic methanol spectra across MM1. Intriguingly, the peak CH3OH Tex = 165.5 ± 0.6 K is offset from MM1’s millimetre continuum peak by 0.22″ ∼ 880 AU, and a region of elevated CH3OH Tex coincides with free-free VLA 5.01 cm continuum, adding to the tentative evidence for a possible unresolved high-mass binary in MM1. In our VLA 1.21 cm data, we report the first NH3(3,3) maser detections towards G19.01−0.03, along with candidate 25 GHz CH3OH 5(2, 3) − 5(1, 4) maser emission; both are spatially and kinematically coincident with 44 GHz Class I CH3OH masers in the MM1 outflow. We also report the ALMA detection of candidate 278.3 GHz Class I CH3OH maser emission towards this outflow, strengthening the connection of these three maser types to MYSO outflows.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.subjectTechniques: interferometricen
dc.subjectStars: formationen
dc.subjectStars: individual: G19.01–0.03en
dc.subjectStars: massiveen
dc.subjectStars: protostarsen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleALMA observations of the Extended Green Object G19.01-0.03 : II. A massive protostar with typical chemical abundances surrounded by four low-mass prestellar core candidatesen
dc.typeJournal articleen
dc.contributor.sponsorScience & Technology Facilities Councilen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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