On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP HI observations. (arXiv:1811.09627v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Teodoro_E/0/1/0/all/0/1">E. M. Di Teodoro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McClure_Griffiths_N/0/1/0/all/0/1">N. M. McClure-Griffiths</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jameson_K/0/1/0/all/0/1">K. E. Jameson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Denes_H/0/1/0/all/0/1">H. Denes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dickey_J/0/1/0/all/0/1">John M. Dickey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stanimirovic_S/0/1/0/all/0/1">S. Stanimirovic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Staveley_Smith_L/0/1/0/all/0/1">L. Staveley-Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anderson_C/0/1/0/all/0/1">C. Anderson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bunton_J/0/1/0/all/0/1">J. D. Bunton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chippendale_A/0/1/0/all/0/1">A. Chippendale</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_Waddell_K/0/1/0/all/0/1">K. Lee-Waddell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacLeod_A/0/1/0/all/0/1">A. MacLeod</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Voronkov_M/0/1/0/all/0/1">M. A Voronkov</a>

We use new high-resolution HI data from the Australian Square Kilometre Array
Pathfinder (ASKAP) to investigate the dynamics of the Small Magellanic Cloud
(SMC). We model the HI 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 at R ~ 2.8
kpc and possibly flattens outwards. In spite of the SMC undergoing strong
gravitational interactions with its neighbours, its HI 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
three-dimensional 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(R<4 kpc) = 1-1.5 x 10^9 solar masses is always required to successfully reproduce the observed rotation curve, implying a large baryon fraction of 30%-40%. We discuss the impact of our assumptions and the limitations of deriving the SMC kinematics and dynamics from HI observations.

We use new high-resolution HI data from the Australian Square Kilometre Array
Pathfinder (ASKAP) to investigate the dynamics of the Small Magellanic Cloud
(SMC). We model the HI 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 at R ~ 2.8
kpc and possibly flattens outwards. In spite of the SMC undergoing strong
gravitational interactions with its neighbours, its HI 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
three-dimensional 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(R<4 kpc) = 1-1.5 x 10^9 solar masses is always required to
successfully reproduce the observed rotation curve, implying a large baryon
fraction of 30%-40%. We discuss the impact of our assumptions and the
limitations of deriving the SMC kinematics and dynamics from HI observations.

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