The halo shape and evolution of polar disc galaxies

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dc.creator Snaith, O. N.
dc.creator Gibson, Brad K.
dc.creator Brook, C. B.
dc.creator Knebe, A.
dc.creator Thacker, Robert John, 1970-
dc.creator Quinn, T. R.
dc.creator Governato, F.
dc.creator Tissera, P. B.
dc.date.accessioned 2018-04-19T15:44:23Z
dc.date.available 2018-04-19T15:44:23Z
dc.date.issued 2012-09
dc.identifier.issn 0035-8711
dc.identifier.uri http://library2.smu.ca/handle/01/27432
dc.description Publisher's Version/PDF
dc.description.abstract We examine the properties and evolution of a simulated polar disc galaxy. This galaxy is composed of two orthogonal discs, one of which contains old stars (old stellar disc) and the other both younger stars and cold gas (polar disc). By exploring the shape of the inner region of the dark matter halo, we are able to confirm that the halo shape is an oblate ellipsoid flattened in the direction of the polar disc. We also note that there is a twist in the shape profile, where the innermost 3 kpc of the halo flattens in the direction perpendicular to the old disc and then aligns with the polar disc out until the virial radius. This result is then compared to the halo shape inferred from the circular velocities of the two discs. We also use the temporal information of the simulation to track the system’s evolution and identify the processes which give rise to this unusual galaxy type. We confirm the proposal that the polar disc galaxy is the result of the last major merger, where the angular moment of the interaction is orthogonal to the angle of the infalling gas. This merger is followed by the resumption of coherent gas infall. We emphasize that the disc is rapidly restored after the major merger and that after this event the galaxy begins to tilt. A significant proportion of the infalling gas comes from filaments. This infalling gas from the filament gives the gas its angular momentum, and, in the case of the polar disc galaxy, the direction of the gas filament does not change before or after the last major merger. en_CA
dc.language.iso en en_CA
dc.publisher Oxford University Press en_CA
dc.relation.uri https://dx.doi.org/10.1111/j.1365-2966.2012.21518.x
dc.rights This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
dc.subject.lcsh Galaxies -- Evolution
dc.subject.lcsh Galaxies -- Formation
dc.subject.lcsh Galactic halos
dc.subject.lcsh Galactic dynamics
dc.subject.lcsh Galaxy mergers
dc.title The halo shape and evolution of polar disc galaxies en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Monthly Notices of the Royal Astronomical Society 425(3), 1967-1979. (2012) en_CA


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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
 
Published Version: https://dx.doi.org/10.1111/j.1365-2966.2012.21518.x
 
 

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