The dynamical evolution of molecular clouds near the Galactic Centre -
  II. Spatial structure and kinematics of simulated clouds
  The evolution of molecular clouds in galactic centres is thought to differ
from that in galactic discs due to a significant influence of the external
gravitational potential. We present a set of numerical simulations of molecular
clouds orbiting on the 100-pc stream of the Central Molecular Zone (the central
$\sim500$ pc of the Galaxy) and characterise their morphological and kinematic
evolution in response to the background potential and eccentric orbital motion.
We find that the clouds are shaped by strong shear and torques, by tidal and
geometric deformation, and by their passage through the orbital pericentre.
Within our simulations, these mechanisms control cloud sizes, aspect ratios,
position angles, filamentary structure, column densities, velocity dispersions,
line-of-sight velocity gradients, spin angular momenta, and kinematic
complexity. By comparing these predictions to observations of clouds on the
Galactic Centre 'dust ridge', we find that our simulations naturally reproduce
a broad range of key observed morphological and kinematic features, which can
be explained in terms of well-understood physical mechanisms. We argue that the
accretion of gas clouds onto the central regions of galaxies, where the
rotation curve turns over and the tidal field is fully compressive, is
accompanied by transformative dynamical changes to the clouds, leading to
collapse and star formation. This can generate an evolutionary progression of
cloud collapse with a common starting point, which either marks the time of
accretion onto the tidally-compressive region or of the most recent pericentre
passage. Together, these processes may naturally produce the synchronised
starbursts observed in numerous (extra)galactic nuclei.
