  The APOSTLE cosmological hydrodynamical simulation suite is a collection of
twelve regions $\sim 5$ Mpc in diameter, selected to resemble the Local Group
of galaxies in terms of kinematics and environment, and re-simulated at high
resolution (minimum gas particle mass of $10^4\,{\rm M}_\odot$) using the
galaxy formation model and calibration developed for the EAGLE project. I
select a sample of dwarf galaxies ($60 < V_{\rm max}/{\rm km}\,{\rm s}^{-1} <
120$) from these simulations and construct synthetic spatially- and
spectrally-resolved observations of their 21-cm emission. Using the $^{3{\rm
D}}$BAROLO tilted-ring modelling tool, I extract rotation curves from the
synthetic data cubes. In many cases, non-circular motions present in the gas
disc hinder the recovery of a rotation curve which accurately traces the
underlying mass distribution; a large central deficit of dark matter, relative
to the predictions of cold dark matter N-body simulations, may then be
erroneously inferred.
