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Williams, GM, Cyganowski, CJ, Brogan, CL et al. (6 more authors) (2022) 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, 509 (1). pp. 748-762. ISSN 0035-8711
Abstract
Using 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-arcsec resolution from 1.05 mm to 5.01 cm wavelengths. Our 0.4 arcsec 1600 au angular resolution ALMA observations reveal a velocity gradient across the millimetre core MM1, oriented perpendicular to the previously known bipolar molecular outflow, which 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 40-70 M (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 fo a partial ellipse, consistent with an inclined ring, with a velocity gradient consistent with that of the theal 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 H ii region, is required to explain the VLA 5 cm emission. The high enclosed mass derived for a source with a moderate bolometric luminosity (104L) suggests that the MM1 disc may feed an unresolved high-mass binary system.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This article has been published in Monthly Notices of the Royal Astronomical Society ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | masers; techniques: interferometric; stars: formation; stars: individual: G19.01-0.03; stars: massive; stars: protostars |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 Jan 2022 15:04 |
Last Modified: | 09 Jan 2025 13:39 |
Status: | Published |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/mnras/stab2973 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:182518 |
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ALMA observations of the Extended Green Object G19.01−0.03: I. A Keplerian disc in a massive protostellar system. (deposited 09 Jan 2025 13:37)
- ALMA observations of the Extended Green Object G19.01−0.03 – I. A Keplerian disc in a massive protostellar system. (deposited 14 Jan 2022 15:04) [Currently Displayed]