Star cluster formation from giant molecular clouds in the Small
  Magellanic Cloud about 2 Gyr ago: their origin, structures, and kinematics
  Recent observations have found that the age distribution of star clusters
(SCs) in the Small Magellanic Cloud (SMC) shows a sharp peak around 2 Gyr ago.
However, it is theoretically unclear what physical processes are responsible
for such sudden formation of SCs in the SMC. Here we investigate whether
massive SCs with initial masses more than $10^5$ $\text{M}_\odot$ can be formed
during tidal interaction of the SMC with the Large Magellanic Cloud (LMC) about
2 Gyr ago, based on our new simulations, which include molecular hydrogen
formation on dust grains and SC formation within giant molecular clouds (GMCs).
We find that the formation of GMCs with masses more than $10^5$
$\text{M}_\odot$ can be dramatically enhanced due to the tidal force of the
LMC-SMC interaction. We also find that gravitationally bound massive SCs can be
formed within these GMCs, though their mean stellar densities ($10^4$
$\text{M}_\odot \text{pc}^{-3}$) are systematically lower than those of the
genuine globular clusters (GCs). All simulated SCs have diffuse extended
stellar envelopes that were formed from multiple merging of sub clusters within
their natal GMCs. Furthermore, we find that some of the simulated SCs can have
considerable global internal rotation and substructures surrounding them. Based
on these simulation results, we discuss the origin of the observed diverse
properties of SCs in the SMC and the physical roles of galaxy interaction in
the formation of massive SCs from GMCs.
