On the dynamics of the Small Magellanic Cloud through high-resolution
  ASKAP 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.
