The halo shape and evolution of polar disc galaxies
Entity
UAM. Departamento de Física TeóricaPublisher
Oxford University Press; Royal Astronomical SocietyDate
2012-09-21Citation
10.1111/j.1365-2966.2012.21518.x
Monthly Notices of the Royal Astronomical Society 425.3 (2012): 1967-1979
ISSN
0035-8711 (print); 1365-2966 (online)DOI
10.1111/j.1365-2966.2012.21518.xFunded by
ONS acknowledges the support of STFC through its PhD Studentship programme (PPA/S/S/2006/4526) and a fellowship from the European Commissions Framework Programme 7, through the Marie Curie Initial Training Network CosmoComp (PITN-GA-2009-238356).BKG, CBB, RJT and AK acknowledge the support of the UK’s Science & Technology Facilities Council (ST/F002432/1, ST/G003025/1).AK further acknowledges support by the SpanishMinisterio de Ciencia e Innovación (MICINN) in Spain through the Ramon y Cajal programme as well as the grants AYA 2009-13875-C03-02, AYA2009- 12792-C03-03, CSD2009-00064 and CAM S2009/ESP-1496. We thank the DEISA consortium, co-funded through EU FP6 project RI-031513 and the FP7 project RI-222919, for supportwithin theDEISA Extreme Computing InitiativeProject
Comunidad de Madrid. S2009/ESP-1496/ASTROMADRID; info:eu-repo/grantAgreement/EC/EP7/222919Editor's Version
http://dx.doi.org/10.1111/j.1365-2966.2012.21518.xSubjects
Galaxies: evolution; Galaxies: formation; Galaxies: haloes; Galaxies: interactions; Galaxies: structure; FísicaNote
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2012 RAS © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Rights
© 2012 RAS; © 2012 The AuthorsAbstract
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 3kpc 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
Files in this item
Google Scholar:Snaith, O. N.
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Gibson, B. K.
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Brook, C. B.
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Knebe, Alexander
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Thacker, R. J.
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Quinn, T. R.
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Governato, F.
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Tissera, P. B.
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