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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.authorIlee, John D.
dc.contributor.authorNazari, Pooneh
dc.contributor.authorKruijssen, J. M. Diederik
dc.contributor.authorSmith, Rowan J.
dc.contributor.authorBonnell, Ian A.
dc.identifier.citationWilliams , G M , Cyganowski , C J , Brogan , C L , Hunter , T R , Ilee , J D , Nazari , P , Kruijssen , J M D , Smith , R J & Bonnell , I A 2021 , ' ALMA observations of the Extended Green Object G19.01-0.03 I. A Keplerian disc in a massive protostellar system ' , Monthly Notices of the Royal Astronomical Society .
dc.identifier.otherPURE: 276294257
dc.identifier.otherPURE UUID: 69470000-fbf6-4d45-8414-b833e2a131bb
dc.identifier.otherScopus: 85121234102
dc.descriptionG.M.W. acknowledges support from the Uk's Science and Technology Facilities Council (STFC) under ST/R000905/1 and ST/M001296/1. C.J.C acknowledges support from the UK's STFC under ST/M001296/1 and J.D.I. acknowledges support from the UK's STFC under ST/T000287/1. J.M.D.K gratefully acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through an Emmy Noether Research Group (grant number KR4801/1-1 and the DFG Schbeihilfe (grant number KR4801/2-1 as well as from the European Research Council (ERC) under the European Enion's Horizon 2020 Research and Innovation programme via the ERC starting grant MUSTANG (grant agreement number 714907)en
dc.description.abstractUsing the Atacama Large Millimetre/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA), we observed the Extended Green Object (EGO) G19.01-0.03 with sub-arcsecond resolution from 1.05 mm to 5.01 cm wavelengths. Our 0.4'' ∼ 1600 AU angular resolution ALMA observations reveal a velocity gradient across the millimetre core MM1, oriented perpendicular to the previously known bipolar molecular outflow, that is consistently traced by 20 lines of 8 molecular species with a range of excitation temperatures, including complex organic molecules (COMs). Kinematic modelling shows the data are well described by models that include a disc in Keplerian rotation and infall, with an enclosed mass of 40-70M⊙ (within a 2000 AU outer radius) for a disc inclination angle of i = 40°, of which 5.4-7.2 M⊙ is attributed to the disc. Our new VLA observations show that the 6.7 GHz Class II methanol masers associated with MM1 form a partial ellipse, consistent with an inclined ring, with a velocity gradient consistent with that of the thermal gas. The disc-to-star mass ratio suggests the disc is likely to be unstable and may be fragmenting into as-yet-undetected low mass stellar companions. Modelling the centimetre--millimetre spectral energy distribution of MM1 shows the ALMA 1.05 mm continuum emission is dominated by dust, whilst a free-free component, interpreted as a hypercompact HII region, is required to explain the VLA ∼ 5 cm emission. The high enclosed mass derived for a source with a moderate bolometric luminosity (∼104 L⊙) suggests that the MM1 disc may feed an unresolved high-mass binary system.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.rightsCopyright © 2021 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at
dc.subjectStars: individual: G19.01-0.03en
dc.subjectStars: formationen
dc.subjectStars: massiveen
dc.subjectStars: protostarsen
dc.subjectTechniques: interferometricen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleALMA observations of the Extended Green Object G19.01-0.03 I. A Keplerian disc in a massive protostellar systemen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews.School of Physics and Astronomyen
dc.contributor.institutionUniversity of St Andrews.Sir James Mackenzie Institute for Early Diagnosisen
dc.description.statusPeer revieweden

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