On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations

E. M. Di Teodoro; N. M. McClure-Griffiths; K. E. Jameson; H. Dénes; John M. Dickey; S. Stanimirović; L. Staveley-Smith; C. Anderson; J. D. Bunton; A. Chippendale; K. Lee-Waddell; A. MacLeod; M. A. Voronkov

doi:10.1093/mnras/sty3095

On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations

E. M. Di Teodoro^*, N. M. McClure-Griffiths, K. E. Jameson, H. Dénes, John M. Dickey, S. Stanimirović, L. Staveley-Smith, C. Anderson, J. D. Bunton, A. Chippendale, K. Lee-Waddell, A. MacLeod, M. A. Voronkov

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

40 Citations (Scopus)

Abstract

We 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 ∼ 4 kpc. After correcting for asymmetric drift, the circular velocity slowly rises to a maximum value of V_c ≃ 55 km s⁻¹ at R ≃ 2.8 kpc 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 M_DM(R < 4 kpc) ≃ 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.

Original language	English
Pages (from-to)	392-406
Number of pages	15
Journal	Monthly Notices of the Royal Astronomical Society
Volume	483
Issue number	1
DOIs	https://doi.org/10.1093/mnras/sty3095
Publication status	Published - 11 Feb 2019

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Di Teodoro, E. M., McClure-Griffiths, N. M., Jameson, K. E., Dénes, H., Dickey, J. M., Stanimirović, S., Staveley-Smith, L., Anderson, C., Bunton, J. D., Chippendale, A., Lee-Waddell, K., MacLeod, A., & Voronkov, M. A. (2019). On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations. Monthly Notices of the Royal Astronomical Society, 483(1), 392-406. https://doi.org/10.1093/mnras/sty3095

@article{488566ad93ce40b19e969a9567ea85e0,

title = "On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations",

abstract = "We 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 ∼ 4 kpc. After correcting for asymmetric drift, the circular velocity slowly rises to a maximum value of Vc ≃ 55 km s−1 at R ≃ 2.8 kpc 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 < 4 kpc) ≃ 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.",

keywords = "Galaxies: dwarf, Galaxies: kinematics and dynamics, Magellanic Clouds",

author = "{Di Teodoro}, {E. M.} and McClure-Griffiths, {N. M.} and Jameson, {K. E.} and H. D{\'e}nes and Dickey, {John M.} and S. Stanimirovi{\'c} and L. Staveley-Smith and C. Anderson and Bunton, {J. D.} and A. Chippendale and K. Lee-Waddell and A. MacLeod and Voronkov, {M. A.}",

note = "Publisher Copyright: {\textcopyright} 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.",

year = "2019",

month = feb,

day = "11",

doi = "10.1093/mnras/sty3095",

language = "English",

volume = "483",

pages = "392--406",

journal = "Monthly Notices of the Royal Astronomical Society",

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Di Teodoro, EM, McClure-Griffiths, NM, Jameson, KE, Dénes, H, Dickey, JM, Stanimirović, S, Staveley-Smith, L, Anderson, C, Bunton, JD, Chippendale, A, Lee-Waddell, K, MacLeod, A & Voronkov, MA 2019, 'On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations', Monthly Notices of the Royal Astronomical Society, vol. 483, no. 1, pp. 392-406. https://doi.org/10.1093/mnras/sty3095

TY - JOUR

T1 - On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations

AU - Di Teodoro, E. M.

AU - McClure-Griffiths, N. M.

AU - Jameson, K. E.

AU - Dénes, H.

AU - Dickey, John M.

AU - Stanimirović, S.

AU - Staveley-Smith, L.

AU - Anderson, C.

AU - Bunton, J. D.

AU - Chippendale, A.

AU - Lee-Waddell, K.

AU - MacLeod, A.

AU - Voronkov, M. A.

PY - 2019/2/11

Y1 - 2019/2/11

N2 - We 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 ∼ 4 kpc. After correcting for asymmetric drift, the circular velocity slowly rises to a maximum value of Vc ≃ 55 km s−1 at R ≃ 2.8 kpc 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 < 4 kpc) ≃ 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.

AB - We 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 ∼ 4 kpc. After correcting for asymmetric drift, the circular velocity slowly rises to a maximum value of Vc ≃ 55 km s−1 at R ≃ 2.8 kpc 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 < 4 kpc) ≃ 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.

KW - Galaxies: dwarf

KW - Galaxies: kinematics and dynamics

KW - Magellanic Clouds

UR - http://www.scopus.com/inward/record.url?scp=85062299946&partnerID=8YFLogxK

U2 - 10.1093/mnras/sty3095

DO - 10.1093/mnras/sty3095

M3 - Article

SN - 0035-8711

VL - 483

SP - 392

EP - 406

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations

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