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dc.contributor.authorSellwood, J A
dc.contributor.authorShen, Juntai
dc.contributor.authorLi, Zhi
dc.date.accessioned2019-08-26T19:21:32Z
dc.date.available2019-08-26T19:21:32Z
dc.date.issued2019-07
dc.identifier.citationJ A Sellwood, Juntai Shen, Zhi Li, The global stability of M33: still a puzzle, Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 4, July 2019, Pages 4710–4723, https://doi.org/10.1093/mnras/stz1145en_US
dc.identifier.issn0035-8711
dc.identifier.doi10.1093/mnras/stz1145
dc.identifier.urihttp://hdl.handle.net/10150/633972
dc.description.abstractThe inner disc of the Local Group galaxy M33 appears to be in settled rotational balance, and near-IR images reveal a mild, large-scale, two-arm spiral pattern with no strong bar. We have constructed N-body models that match all the extensive observational data on the kinematics and surface density of stars and gas in the inner part of M33. We rind that currently favoured models are unstable to the formation of a strong bar of semimajor axis 2 less than or similar to a(B) less than or similar to 3 kpc within 1 Gyr, which changes the dynamical properties of the models to become inconsistent with the current, apparently well-settled, state. The formation of a bar is unaffected by how: the gas component is modelled, by increasing the mass of the nuclear star cluster, or by making the dark matter halo counter-rotate, but it can be prevented by either reducing the mass-to-light ratio of the stars to Y-V similar to 0.6 or Y-K similar to 0.23 in solar units or by increasing the random motions of the stars. Also a shorter and weaker bar results when the halo is rigid and unresponsive. However, all three near-stable models support multi-arm spirals, and not the observed largescale hi-symmetric spiral, A two-arm spiral pattern could perhaps be tidally induced, but such a model would require an implausibly low-mass disc to avoid a bar and there is no visible culprit:. Thus the survival of the current state of this exceptionally well-studied galaxy is not yet understood. We also suspect that many other unbarred galaxies present a similar puzzle.en_US
dc.description.sponsorshipChinese Academy of Sciences President's International Fellowship Initiative [2018VMA0051]; NSF [PHY-1748958]; National Key R&D Program of China [2018YFA0404501]; National Natural Science Foundation of China [11773052, 11761131016, 11333003]; China-Chile joint grant from CASSACA; Newton Advanced Fellowship - Royal Society; Newton Funden_US
dc.language.isoenen_US
dc.publisherOXFORD UNIV PRESSen_US
dc.rights© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Societyen_US
dc.subjectgalaxies: evolutionen_US
dc.subjectgalaxies: kinematics and dynamicsen_US
dc.subjectLocal Groupen_US
dc.subjectgalaxies: spiralen_US
dc.titleThe global stability of M33: still a puzzleen_US
dc.typeArticleen_US
dc.identifier.eissn1365-2966
dc.contributor.departmentUniv Arizona, Steward Observen_US
dc.identifier.journalMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETYen_US
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en_US
dc.eprint.versionFinal published versionen_US
dc.source.volume486
dc.source.issue4
dc.source.beginpage4710-4723
refterms.dateFOA2019-08-26T19:21:33Z


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