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Bars in dark-matter-dominated dwarf galaxy discs

Marasco, A.; Oman, K.A.; Navarro, J.F.; Frenk, C.S.; Oosterloo, T.

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A. Marasco

K.A. Oman

J.F. Navarro

T. Oosterloo


We study the shape and kinematics of simulated dwarf galaxy discs in the APOSTLE suite of Λ cold dark matter (ΛCDM) cosmological hydrodynamical simulations. We find that a large fraction of these gas-rich, star-forming discs show weak bars in their stellar component, despite being dark-matter-dominated systems. The bar pattern shape and orientation reflect the ellipticity of the dark matter potential, and its rotation is locked to the slow figure rotation of the triaxial dark halo. The bar-like nature of the potential induces non-circular motions in the gas component, including strong bisymmetric flows that can be readily seen as m = 3 harmonic perturbations in the H I line-of-sight velocity fields. Similar bisymmetric flows are seen in many galaxies of The HI Nearby Galaxy Survey (THINGS) and Local Irregulars That Trace Luminosity Extremes THINGS (LITTLE THINGS), although on average their amplitudes are a factor of ∼2 weaker than in our simulated discs. Our results indicate that bar-like patterns may arise even when baryons are not dominant, and that they are common enough to warrant careful consideration when analysing the gas kinematics of dwarf galaxy discs.


Marasco, A., Oman, K., Navarro, J., Frenk, C., & Oosterloo, T. (2018). Bars in dark-matter-dominated dwarf galaxy discs. Monthly Notices of the Royal Astronomical Society, 476(2), 2168-2176.

Journal Article Type Article
Acceptance Date Jan 20, 2018
Online Publication Date Feb 9, 2018
Publication Date May 11, 2018
Deposit Date Apr 5, 2018
Publicly Available Date Apr 6, 2018
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 476
Issue 2
Pages 2168-2176


Published Journal Article (4.2 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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