133221 - On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP HI observations.pdf (2.77 MB)
On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP HI observations
journal contribution
posted on 2023-05-20, 04:25 authored by Di Teodoro, EM, McClure-Griffiths, NM, Jameson, KE, Denes, H, John DickeyJohn Dickey, Stanimirovic, S, Staveley-Smith, L, Anderson, C, Bunton, JD, Chippendale, A, Lee-Waddell, K, MacLeod, A, Voronkov, MAWe use new high-resolution H i data from the Australian Square Kilometre Array Pathfinder to investigate the dynamics of the Small Magellanic Cloud (SMC). We model the H i gas component as a rotating disc of non-negligible angular size, moving into the plane of the sky, and undergoing nutation/precession motions. We derive a high-resolution (∼ 10 pc) rotation curve of the SMC out to R ∼ 4kpc. After correcting for asymmetric drift, the circular velocity slowly rises to a maximum value of Vc ≃ 55kms-1 at R ≃ 2.8kpc and possibly flattens outwards. In spite of the SMC undergoing strong gravitational interactions with its neighbours, its H i rotation curve is akin to that of many isolated gas-rich dwarf galaxies. We decompose the rotation curve and explore different dynamical models to deal with the unknown 3D shape of the mass components (gas, stars, and dark matter). We find that, for reasonable mass-to-light ratios, a dominant dark matter halo with mass MDM(R < 4kpc) ≃ 1-1.5×109 M⊙ is always required to successfully reproduce the observed rotation curve, implying a large baryon fraction of 30 per cent - 40 per cent. We discuss the impact of our assumptions and the limitations of deriving the SMC kinematics and dynamics from H i observations.
History
Publication title
Monthly Notices of the Royal Astronomical SocietyVolume
483Pagination
392-406ISSN
0035-8711Department/School
School of Natural SciencesPublisher
Blackwell Publishing LtdPlace of publication
9600 Garsington Rd, Oxford, England, Oxon, Ox4 2DgRights statement
Copyright 2018 The Authors. 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.Repository Status
- Open