Kyle A Oman
Non-circular motions and the diversity of dwarf galaxy rotation curves
Oman, Kyle A; Marasco, Antonino; Navarro, Julio F; Frenk, Carlos S; Schaye, Joop; Benítez-Llambay, Alejandro
Authors
Antonino Marasco
Julio F Navarro
Professor Carlos Frenk c.s.frenk@durham.ac.uk
Professor
Joop Schaye
Alejandro Benítez-Llambay
Abstract
We use mock interferometric H I measurements and a conventional tilted-ring modelling procedure to estimate circular velocity curves of dwarf galaxy discs from the APOSTLE suite of Λ cold dark matter cosmological hydrodynamical simulations. The modelling yields a large diversity of rotation curves for an individual galaxy at fixed inclination, depending on the line-of-sight orientation. The diversity is driven by non-circular motions in the gas; in particular, by strong bisymmetric fluctuations in the azimuthal velocities that the tilted-ring model is ill-suited to account for and that are difficult to detect in model residuals. Large misestimates of the circular velocity arise when the kinematic major axis coincides with the extrema of the fluctuation pattern, in some cases mimicking the presence of kiloparsec-scale density ‘cores’, when none are actually present. The thickness of APOSTLE discs compounds this effect: more slowly rotating extra-planar gas systematically reduces the average line-of-sight speeds. The recovered rotation curves thus tend to underestimate the true circular velocity of APOSTLE galaxies in the inner regions. Non-circular motions provide an appealing explanation for the large apparent cores observed in galaxies such as DDO 47 and DDO 87, where the model residuals suggest that such motions might have affected estimates of the inner circular velocities. Although residuals from tilted-ring models in the simulations appear larger than in observed galaxies, our results suggest that non-circular motions should be carefully taken into account when considering the evidence for dark matter cores in individual galaxies.
Citation
Oman, K. A., Marasco, A., Navarro, J. F., Frenk, C. S., Schaye, J., & Benítez-Llambay, A. (2018). Non-circular motions and the diversity of dwarf galaxy rotation curves. Monthly Notices of the Royal Astronomical Society, 482(1), 821-847. https://doi.org/10.1093/mnras/sty2687
Journal Article Type | Article |
---|---|
Acceptance Date | Sep 27, 2018 |
Online Publication Date | Oct 4, 2018 |
Publication Date | Oct 4, 2018 |
Deposit Date | Oct 31, 2018 |
Publicly Available Date | Oct 31, 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 | 482 |
Issue | 1 |
Pages | 821-847 |
DOI | https://doi.org/10.1093/mnras/sty2687 |
Public URL | https://durham-repository.worktribe.com/output/1315031 |
Files
Published Journal Article
(5 Mb)
PDF
Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
You might also like
The impact and response of mini-haloes and the interhalo medium on cosmic reionization
(2024)
Journal Article
The diversity of rotation curves of simulated galaxies with cusps and cores
(2023)
Journal Article
Baryonic clues to the puzzling diversity of dwarf galaxy rotation curves
(2020)
Journal Article
Downloadable Citations
About Durham Research Online (DRO)
Administrator e-mail: dro.admin@durham.ac.uk
This application uses the following open-source libraries:
SheetJS Community Edition
Apache License Version 2.0 (http://www.apache.org/licenses/)
PDF.js
Apache License Version 2.0 (http://www.apache.org/licenses/)
Font Awesome
SIL OFL 1.1 (http://scripts.sil.org/OFL)
MIT License (http://opensource.org/licenses/mit-license.html)
CC BY 3.0 ( http://creativecommons.org/licenses/by/3.0/)
Powered by Worktribe © 2024
Advanced Search